Psalm 139 was written by king David (Psalm 139:1a).
God knows everything about us (Psalm 139:1b–4), see God is omniscient
in God's Attributes.
God had plans for us before we were born: "Your eyes saw my unformed body;
all the days ordained for me were written in your book before one of them came to be." (Psalm 139:16 (NIV)). This speaks against abortion. For example, God had plans for Samson even before his mother became conceived (Judges 13:2–7).
"You hem me in, behind and before, and lay your hand upon me." (Psalm 139:5).
God always protects us. Our lives are in his hands.
"For my thoughts are not your thoughts, neither are your ways my ways, declares the Lord. For as the heavens are higher than the Earth, so are my ways higher than your ways and my thoughts than your thoughts." (Isaiah 55:8–9). We can't always understand God's way or God's knowledge and wisdom (Psalm 139:6).
"How precious to me are your thoughts, O God! How vast is the sum of them!"
(Psalm 139:17). God's thoughts are of great value. It also means that God's word, the Bible, is very precious to us.
God isn't limited by space, he can be present everywhere at the same time (Psalm 139:7–10), see God is omnipresent in God's Attributes.
David wrote: "Search me, O God, and know my heart! Try me (test me) and know my thoughts! And see if there be any grievous way in me, and lead me in the way everlasting!" (Psalm 139:23–24). David asks the Lord if anything is happening in his life that grieves the Lord, causing discomfort for the Lord. The Holy Spirit didn't indwell people in the Old Testament, see Jesus the Light of the World. Yet David prayed this prayer. This was one of the things that made him a man after God's own heart. And David wasn't perfect. David asked God to know his own heart, to know what was behind his thoughts. David confessed and repented when God revealed flaws in his life. We have a great propensity for self-deception. We therefore need God to reveal things in our lives so that we become aware of them.
David wanted God to lead him in the way of life that God wanted him to live
(Psalm 143:10, Isaiah 55:8–9). As Christians we need the power of the Holy Spirit
to live such a life (Eph 3:16–19, Proverbs 3:5–7).
See also The Book of Psalms.
