https://www.mljtrust.org/sermons-online/numbers-11-4-6/man-and-sin/

What is sin? Many people say that sin is merely something that we do. In this sermon on sin from Numbers 11:4–6 titled “Man and Sin,” Dr. Martyn Lloyd-Jones shows that this is not the biblical view of sin. In the book of Numbers, sin is shown as an attitude and disposition, not only an action. This is why sin is so bad, because it comes out of the very heart and determines motives. The grumbling of the Israelites was not simply their dissatisfaction with life, but it was a dissatisfaction with God. When they said that they wanted meat, they showed that worldly desire for food was more important than trusting God. This was all born out of their sinful desires. What is the answer to the sin that has corrupted everyone’s desires? The answer is found in what God has done in Jesus Christ on the cross. Sin is so bad that God Himself came to die for sinners. All who trust in Jesus are made righteous and children of God. They are given a new heart and mind and freed from sin and death because of Christ’s death. This is the only means of overcoming sin and death.