In a court of law, it’s often difficult to determine the truth of a matter. The memory of eyewitnesses can be unreliable, and people sometimes don’t tell the truth. Evidence may be contradictory, and it’s rare for someone to know all the facts of a situation. However, there is someone whose knowledge of all things is complete and perfect—a witness who is on our side.

That witness is God. He knows everything about us, even the things hidden from us. Frequently in the psalms, David asks God to come to his defence, against those who falsely accuse him. In Psalm 139, however, the lies people are spreading are lies about God (vv. 19–22). Perhaps they are taking His name in vain (Exodus 20:7) or attacking His character. Since David takes God’s side, it’s possible that the false accusations were being levelled against him as well.

David begins by acknowledging that God knows every detail of his life, including what he will say before he even speaks (Psalm 139:1–6). Along with that, God is present everywhere. No-one can run or hide from His presence (vv. 7–12). Then David returns to the theme of God’s intimate knowledge of him (vv. 13–18). Long before the invention of ultrasound, God knew the baby in the womb—from the moment of conception. In fact, God’s knowledge goes beyond what He sees, to all that He has planned. God knew and determined everyone’s birthday and, similarly, the day of each person’s death (v. 16).

There is so much we can learn from this psalm. First, we can be confident that, while courts on earth may make wrong or unfair judgments, we have a God who knows all the facts and, at the end of all time, will bring just judgments. Second, we can be confident that we’re never alone. Wherever we are, God is there, watching over us and fulfilling His good plans for us.

Finally, we can be comforted by the knowledge that birth and death are in God’s hands. The unborn child is known to God and precious to Him. And while death may sometimes take us by surprise, we can be confident that we won’t die a single day before or after what He has determined in His goodness and mercy.

Armed with this understanding of God’s complete knowledge, David concludes by inviting the just and all-loving God to search him and know his heart (vv. 23-24). Of course, he’s not claiming to be perfect, but his conscience is clear and his heart is pure (see Matthew 5:8). He knows that the path he walks will lead him to everlasting life (Psalm 139:24). This is our hope and comfort, as well.