What does Psalm 139:4 mean?
In this verse the psalmist, David, declares that the all-knowing God foreknows even the words he is about to speak. God knows what we are thinking and about to say. No wonder David declared at the end of the psalm: "Search me, O God, and know my heart! Try me and know my thoughts!" (Psalm 139:23).What we say with our mouths results from the words we form in our minds, and those words form out of our thoughts. The fact that God knows the words we are about to speak should cause us to think carefully about our speech and our thoughts. Our words should be wholesome, healthful, and edifying. Colossians 4:6 exhorts: "Let your speech always be gracious, seasoned with salt, so that you may know how you ought to answer each person." Ephesians 4:25 says we should speak the truth with our neighbor. In the world we are surrounded by foul speech, lies, and words meant to tear down. We must resist the temptation to speak in kind. We should not engage in corrupt talk, but speak only words that are true and that build others up, "that it may give grace to those who hear" (Ephesians 4:29).
Psalm 139:1–6 extols God's infinite knowledge. David views God as knowing all about him: when he sits down and gets up, his thoughts and conduct, and even the words that are in his mind before he expresses them. He states that God's knowledge is far beyond his comprehension. This section of the psalm precedes the section that focuses on God's omnipresence—his presence everywhere.
In this psalm David marvels at God's amazing characteristics. God knows everything about him: where he goes, all David's thoughts and everything about his conduct. The Lord knows what David will say even before David says it. There is no place David can go that God isn't already present. David marvels at God's creative work in the womb. He is thankful for God's innumerable thoughts for him and for God's presence day and night. Finally, David's thoughts turn to the wicked. He considers them God's enemies and his, and longs for God to slay them. David is disgusted by evil people because they rail against God and take His name in vain. He asks God to search his heart to see if any sin is there, and he asks God to lead him in the way everlasting.
