What does Proverbs 16:9 mean?

This echoes a similar proverb, recorded in verse 1 (Proverbs 16:1). A person can plan out every aspect of their life; yet God is the one who ultimately decides what will happen. New Testament writers such as Paul (Romans 9:20–21) and James (James 4:13–15) reinforce this idea. Nothing we intend can override God's will (Psalm 33:10; Job 42:2). That does not mean planning is wrong—but what we plan needs to be prepared in a spirit of humility and obedience.

Isaiah 53:6 describes human beings as sheep that have wandered away from God. We have all gone astray, and regardless of how intelligent a person is, "it is not in man who walks to direct his steps" (Jeremiah 10:23). Nevertheless, if a person seeks God's will and walks by the Spirit in the light of God's Word, the Lord will approve and guide his steps. Paul's letter to the Ephesians gives good counsel about how believers should walk. It tells us to "walk in a manner worthy of the calling to which you have been called" (Ephesians 4:1), walk not "as [unbelievers] do, in the futility of their minds" (Ephesians 4:17), "walk in love" (Ephesians 5:2), "walk as children of light" (Ephesians 5:8), and walk wisely (Ephesians 5:15). Galatians 5:16 instructs us to "walk by the Spirit."