Psalm 139:17-18 meaning

With everything that God knows about us (see previous commentary on v. 13-16 ), David marvels at how precious God's thoughts are. God's thoughts have immense value and their mere existence is worth revering. Everything that exists began in the thoughts of God, so that it is hard to understand how vast is the sum of them. The things that God knows are so numerous that if we should count them, they would outnumber the sand.

How do we know God's thoughts? By listening to Him. God speaks to us in many ways. His creation speaks to us, if we have the ears to hear (Psalm 19:1-4, Romans 1:19-20). His written word speaks to us, if we have ears to hear (James 1:21, 2 Timothy 3:16, Revelation 3:19-20).

David is emphasizing two things: first, that God's thoughts ought to be of great value to us and worthy of our contemplation; and second, that God's thoughts are too numerous for us to know, let alone for us to try and understand them all. Yet, when we listen to God, we gain immense benefit.

With all that God knows and all that He is, He does not forget us. David knows that he can fall asleep every night with confidence, saying that when I awake, I am still with You. God does not take His relationship with us lightly. Since He exists outside of the confines of space and time, He is there when we go to bed and when we wake up, not neglecting us for other things.