What does Proverbs 15:7 mean?

This accredits spreading of knowledge to those who are wise. Those who honor godly truth speak wisely and others benefit from their words. They speak the truth and share it freely.

This is certainly true of believers who share the gospel with others. They present the facts of the gospel: First, that Christ died for our sins in accordance with the Scriptures. Second, that He was buried. Third, that He was raised on the third day in accordance with the Scriptures. Fourth, that He appeared to Peter, to the twelve disciples, to more than 500 believers, to James, to all the apostles, and to the apostle Paul (1 Corinthians 15:3–8).

It is important that witnesses in a court of law give truthful testimony about what they saw, heard, or experienced. It is also important that believers, who are Jesus' witnesses, share the truth about Jesus and what He has accomplished in their lives (Acts 1:8). Fools ignore or reject the facts about Jesus, and they also reject Jesus. Therefore, they cannot spread the knowledge of Him with others.