In I Corinthians 5, the apostle Paul wrote: “Christ our passover is sacrificed for us: therefore let us keep the feast” (vs. 7-8).

Soon we will be following this instruction. After observing the New Testament Passover on the evening of Abib 14 in remembrance of Jesus Christ, we then proceed to the next commanded observance: “the feast.”

The Feast of Unleavened Bread (Ex. 12:17; Lev. 23:6), also called the Days of Unleavened Bread (Acts 12:3; 20:6) and the seven days of Passover (Ezek. 45:21), begins the following evening with the Night to Be Much Observed.

Packed into Paul’s words is the understanding that to reach that point, we had to prepare. We recognized Jesus as our Passover, as the verse says, and we also examined ourselves, deleavened our homes, arranged time off from work or school, baked or purchased unleavened bread to have on hand, and did various other things to be ready, physically and spiritually.

There is so much going on, by the time we say goodbye after dinner on the Night to Be Much Observed, “let us keep the feast” can almost feel like “let us catch our breath.” But Paul goes on to explain what we should focus on now that the feast is here. Our focus on preparation is now replaced by two simple yet powerful concepts.

I Corinthians 5:8 continues, “Therefore let us keep the feast, not with old leaven, neither with the leaven of malice and wickedness; but with the unleavened bread of sincerity and truth.”

Our self-examination alerts us to the spiritual “old leaven”—sin—that we need to remove. Upon taking the Passover symbols, we receive a clean slate. But God does not want our spiritual slates to remain blank. He wants us to fill our minds with sincerity and truth.

It is easy to quickly read past that part of the verse or see it as sort of a general affirmation of living the right way. But God carefully chose these words. They sum up exactly what this feast is all about.

The Feast of Unleavened Bread teaches us to live with sincerity and truth during these days and as a way of life.

From Joshua to Paul

God has desired sincerity and truth from His people for thousands of years—not just in the New Testament Church (Matt. 16:18), which we are part of today, but also in the Old Testament “church in the wilderness” (Acts 7:38).

Near the end of his life, Joshua told ancient Israel: “Now therefore fear the Lord, and serve Him in sincerity and in truth: and put away the gods which your fathers served on the other side of the flood, and in Egypt; and serve you the Lord” (24:14).

According to the Outline of Biblical Usage, the Hebrew word for sincerity, tamim, can mean “sound, wholesome, unimpaired, innocent, having integrity” and “what is complete or entirely in accord with truth and fact.”

The Hebrew word for truth, emet, can mean “firmness, faithfulness, truth” and applies to truth “as spoken, of testimony and judgment, of divine instruction, truth as a body of ethical or religious knowledge,” and “true doctrine.”

Take a moment to appreciate just how comprehensive these words are. God wanted Israel then and us today to serve Him in a wholesome, unimpaired, innocent way. There is no room for compromise in this command.

Joshua said this after reminding the Israelites of all that God had done to deliver them. Take time to study the entire chapter. It lays out God’s plan of working through Abraham, Isaac, Jacob and Moses to deliver Israel out of bondage in Egypt and into the Promised Land.

There is a rich parallel here for us. God the Father called us out of this world and opened our minds to the truth (John 6:44). Jesus Christ paid the death penalty in our place so we would not need to pay that price ourselves (II Cor. 5:21). God also worked through various human instruments as He did with Israel to teach, counsel and prepare us to enter His Church (Rom. 10:17; Acts 8:31).

With ancient Israel and with us, one thing should be clear: Deliverance must be followed by commitment.

Joshua was exhorting the people not to waste God’s miraculous intervention. They could still fail if they did not fully dedicate themselves to Him.

The same is true of us. God has delivered us out of sin. But we could still return to spiritual bondage, either through our choices (Heb. 10:26) or through neglect (2:3).

The people told Joshua, “The Lord our God will we serve, and His voice will we obey” (Josh. 24:24). That should be our mindset too. Although Israel went on to have a mixed track record of obedience, they were convicted when they heard Joshua’s words.

We are spiritual Israel (Gal. 6:16), with God’s Spirit working in us. We can reach God’s standards of sincerity and truth, as Joshua told Israel in the Old Testament and Paul commanded Christians in the New Testament.

Living with Sincerity

Jesus Christ warned His disciples about a group of people in the first century for whom insincerity was a defining character trait. He said: “Beware you of the leaven of the Pharisees, which is hypocrisy” (Luke 12:1).

The Pharisees took great care to appear righteous to others, but they were utterly wicked in their inner thoughts and motives. They were hypocrites.

Christ added in Matthew 23:27 that the Pharisees were “like unto whited sepulchers [tombs], which indeed appear beautiful outward, but are within full of dead men’s bones, and of all uncleanness.” Their smooth words and careful appearance were at odds with what was in their hearts—hatred and jealousy toward God in the flesh.

This is an extreme example, but God recorded it for our benefit. No one turns into a Pharisee overnight, yet we could be tempted to portray ourselves one way while acting another. That is why Christ likened hypocrisy, or insincerity, to leaven. Galatians 5:9 warns, “A little leaven leavens the whole lump.”

It starts subtly. We tell a half-truth. We leap into action to serve when the minister is in the room but stand in the corner when he is not watching. We tell our children to study the Bible every day but do not do so ourselves. We nod our heads to a sermon but do not really believe it. We write in a card that we are praying for a person but never get around to actually doing it.

These are just a few examples. But hypocrisy can blossom into a way of life if we allow it.

Romans 12:9 says, “Let love be without dissimulation.” Other translations are clearer than the King James. The New Living Translation says, “Don’t just pretend to love others. Really love them.” The New King James Version says, “Let love be without hypocrisy.” And the Weymouth New Testament says, “Let your love be perfectly sincere.”

This all ties back to Paul’s instruction in I Corinthians 5:8 to keep the feast “with the unleavened bread of sincerity and truth.” We are to practice sincerity, not hypocrisy. Sincerity means our outward actions match our inward motives.

The Greek word for sincerity is similar to the Hebrew definition we looked at earlier. It means “purity, sincerity, ingenuousness” (Outline of Biblical Usage). How do we apply this quality in our lives?

First, we are sincere toward God. We do not justify ourselves, make excuses for our conduct or assume God is pleased with us if His Word shows otherwise. We come before God honestly and vulnerably in prayer. We strive for wholehearted obedience. When we slip up, we carefully seek repentance, not simply going through the motions. If needed, we beseech God like King David did in Psalm 51.

It has often been said that character is what a person does when no one is watching. But someone is always watching: God.

Proverbs 15 says, “The eyes of the Lord are in every place, beholding the evil and the good” (vs. 3). This verse should both inspire and sober us. God sees the good we do, even if we do not get recognition from people. But God also sees the bad we do, even if it is not apparent to others.

Living with sincerity requires choosing to do what is right even in unseen moments.

We also practice sincerity in our relationships with other people. We say what we mean and mean what we say. The Ninth Commandment is, “You shall not bear false witness against your neighbor” (Ex. 20:16). That means we do not lie, but the principle also applies to subtle motives and intentions.

Whether we are at home with family, in the workplace, at Sabbath services, or anywhere else, we avoid manipulation, flattery and hidden agendas, even if people around us are living differently. We are real and genuine, even when it costs us something.

That does not mean we just blather whatever is on our mind with no filter. It means we do not misrepresent who we really are.

It is also important to be sincere with yourself. Jeremiah 17:9 says: “The heart is deceitful above all things, and desperately wicked: who can know it?” Our natural tendency is to deceive ourselves—to avoid confronting how “desperately wicked” the human heart can be.

We must be on guard against pride, which makes us think we are better than we really are. Galatians 6:3 says, “For if a man think himself to be something, when he is nothing, he deceives himself.”

Likewise, we could also fall into self-deception by beating ourselves up and letting thoughts of fear and anxiety rule over us, selling short the work God is doing in our lives (Phil. 1:6). Both extremes must be avoided.

Psalm 32:2 says, “Blessed is the man unto whom the Lord imputes not iniquity, and in whose spirit there is no guile [deceit].” By practicing sincerity in every area of life, we will be blessed by God.

Living by Truth

Personal sincerity is critically important. But being sincere by itself is not enough. People can be sincere but sincerely wrong. Truth is the second component to Paul’s instruction in I Corinthians 5:8.

As with sincerity, the Greek word here is similar to the word for truth in the Old Testament. But it bears its own examination.

Truth in the New Testament can mean “what is true in any matter under consideration,” “what is true in things appertaining to God and the duties of man, moral and religious truth,” and even “the truth as taught in the Christian religion, respecting God and the execution of his purposes through Christ…opposing alike to the superstitions of the Gentiles and the inventions of the Jews, and the corrupt opinions and precepts of false teachers even among Christians” (Outline of Biblical Usage).

This is comprehensive!

Although such a level of detail is helpful, Jesus in John 17:17 boiled this down to a much simpler definition. He prayed, “Sanctify them through Your truth: Your word is truth.”

Do not overcomplicate what truth is. Truth is what is written in God’s Word, the Bible.

Our personal moral standards, no matter how sincere, must conform to what God recorded in His instruction manual for mankind. Being sincere but not living by truth is futile. We need to know and apply the truth God gives us.

We should always be willing to compare our personal ideas and standards to what God says. This helps us see where our thinking differs from God’s. If we find we are out of step, we change. This is a lifelong process.

The prophet Isaiah recorded, “My thoughts are not your thoughts, neither are your ways My ways, says the Lord. For as the heavens are higher than the earth, so are My ways higher than your ways, and My thoughts than your thoughts” (55:8-9).

If we are not studying diligently, we could slowly start to believe God’s standards are different than they really are. Ecclesiastes 7 warns of this. Verse 16 says, “Be not righteous over much; neither make yourself over wise: why should you destroy yourself?”

If we are not careful, we could be more “righteous” and “wise” than what God’s Word actually says!

The opposite is also true: “Be not over much wicked, neither be you foolish: why should you die before your time?” (vs. 17).

We should be balanced. Not giving ourselves a pass where God does not, but also not blowing smaller matters out of proportion.

To live by truth, we need to feed our minds with that truth. We should prove and re-prove the basic doctrines of the Bible and take advantage of every tool the Church gives us—magazines, sermons, Bible studies and more.

Also remember that Paul talked about the “unleavened bread of sincerity and truth.” Eating unleavened bread during this festival pictures taking God’s Word into our bodies.

Exodus 13 says, “Unleavened bread shall be eaten seven days…and it shall be for a sign unto you upon your hand, and for a memorial between your eyes, that the Lord’s law may be in your mouth” (vs. 7, 9). And Christ added in Matthew 4:4, “Man shall not live by bread alone, but by every word that proceeds out of the mouth of God.”

Next time you reach for a piece of matzo, think of God’s Law being in your mouth. The truth nourishes us and sustains us so we can live the unleavened life God wants.

From a Feast to a Way of Life

The two elements of I Corinthians 5:8 are inseparable. Truth establishes the standards we live by. Sincerity addresses our inner thoughts and motives.

Truth without sincerity can become outward compliance without inward change. Sincerity without truth can drift into self-defined religion. We need both.

David prayed, “Behold, You desire truth in the inward parts: and in the hidden part You shall make me to know wisdom” (Psa. 51:6). And Philippians 1 says, “This I pray…that you may be sincere and without offense till the day of Christ” (vs. 9-10).

The Days of Unleavened Bread are a concentrated opportunity to live this way. We have a clean slate after Passover. We can now move forward, choosing to “walk in newness of life” (Rom. 6:4), becoming more sincere and truthful while guarding against compromise. During this year’s feast, take time to study these concepts more and reflect on them in your life.

When Joshua told Israel to live by sincerity and truth, he was not giving a Holy Day sermon—this was just the standard God wanted them to live by. Likewise, Paul cited these elements as key to the Spring Holy Days, but no one could think that the sun setting after the Last Day of Unleavened Bread means we can be insincere hypocrites.

These concepts are meant to be applied in our Christian lives all the time.

Determine to “keep the feast” this year with sincerity and truth and make those qualities integral to who you are, even after the Days of Unleavened Bread are behind you.