Question: "What did Jesus mean when He said 'he who is without sin can cast the first stone'?"
Answer: Jesus’ statement “If any one of you is without sin, let him be the first to throw a stone at her” is found in John 8:1-11. Jesus was teaching in the temple when the scribes and Pharisees brought to Him a woman who had been caught in the act of adultery, and they asked Him if she should be stoned as required by the Law of Moses. However, they cared nothing about this woman; they were using her to trap Jesus. In their minds, if He told them to set the woman free, they could claim He did not hold to the Law of Moses. If He told them to stone her they could claim He was not the Savior, and if He said nothing they could claim He lacked wisdom. Jesus did not answer immediately but stooped and wrote something on the ground, and they kept pressing Him. Finally the Lord said, in essence, “Go ahead and stone her because that is what the Law requires. But the Law also requires that the first stone be thrown by a person that is sinless in connection with this charge” (John 8:6-7).
There is no doubt that this woman was guilty of a capital offense and that the Law required that she be stoned, but the Law also required that the guilty man be stoned as well (Deuteronomy 22:22), that witnesses be produced, and that a witness begin the execution. But the Jewish leaders came with venom against Jesus and were thwarted by their own single-minded hate. They did not produce the guilty man and they were unwilling or unable to produce the required witnesses. We do not know what Jesus wrote, but after He wrote a second time the Jews left one by one, from the oldest to the youngest, without saying another word. Jesus then set the woman free with a warning to her to sin no more.
From this passage we learn that we do not accuse others unless we first thoroughly search our own hearts and minds to make certain that we are pure in every possible aspect (Matthew 7:3). Also, if we must admonish someone, we should do so as instructed in Scripture; we always look to God’s glory and never cause unnecessary division or harm (Matthew 18:15), but we do work to keep the church pure. Moreover, Jesus was the only sinless person in the temple scene, and instead of condemning the woman He looked ahead to His work on the cross and offered her life. Likewise we should use every possible opportunity to forgive and to reach out with the gospel and the love of Christ, always remembering that we, too, are sinners in need of the Savior (Romans 3:23).