What does Proverbs 2:8 mean?

Verses 6 and 7 provided reasons to be confident when we seek wisdom and understanding from God. Those who do will find He has plenty of both to offer, and will act as a "shield" of protection for us. This is related to the concept of living virtuously, which in ancient philosophy meant pursuing several key traits. Verse 7, in particular, grounds our sense of courage in trust. As with other biblical passages (Hebrews 6:13–20), this kind of reassurance is meant to be "encouraging"—literally, "that which gives others courage."

Here, verse 8 concludes by giving additional examples of why we can be courageous in pursuing the wisdom of the Lord. The two words used in this verse which are translated as "guard, watch over, or preserve" are from the Hebrew root words natsar and shamar. These literally mean to keep a watchful guard over, or to keep protectively. If God calls us to be a light (Matthew 5:14), He will be the keeper of the lighthouse. If God calls us to be salt (Matthew 5:13), He will ensure the salt does not lose its flavor. No one can stand against God. If He is our keeper, we too can live courageously (Romans 8:31).

This verse also uses the term justice, another key virtue featured in ancient philosophy. Wisdom—the proper application of knowledge—results in justice when we act as God wills; this requires both faith and courage, which ultimately only confidence in God can supply. Upcoming verses will give more details on the meaning of justice in the book of Proverbs.