1 O LORD, you have searched meThe Commentary and Reflection on this Psalm in the New Interpreter's Bible, Abingdon Press, note that "[e]xplicitly theological concepts like omniscience and omnipresence are often applied by interpreters of Psalm 139 [but] almost inevitably these terms will fail to do just to the psalm, since the psalmist did not intend to articulate systematically a doctrine of God."
and you know me.
2 You know when I sit and when I rise;
you perceive my thoughts from afar.
3 You discern my going out and my lying down;
you are familiar with all my ways.
4 Before a word is on my tongue
you know it completely, O LORD.
5 You hem me in—behind and before;
you have laid your hand upon me.
6 Such knowledge is too wonderful for me,
too lofty for me to attain.
13 For you created my inmost being;
you knit me together in my mother's womb.
14 I praise you because I am fearfully and wonderfully made;
your works are wonderful,
I know that full well.
15 My frame was not hidden from you
when I was made in the secret place.
When I was woven together in the depths of the earth,
16 your eyes saw my unformed body.
All the days ordained for me
were written in your book
before one of them came to be.
17 How precious to me are your thoughts, O God!
How vast is the sum of them!
That's good, because if the psalmist was articulating a systematic doctrine, we would pretty much have to accept predistination, not to mention the idea that life begins at conception. I don't want to do either of those things.
As it is, all I have to do is figure out what it means for God to know me so intimately that I cannot hide from God. Is that good, or does it "hem me in"? This psalm seems to play with the comfort and accountability of knowing you are never alone. It's like when a friend or loved one reminds you of "who you are." Sometimes it can be a joy; sometimes it can be hard.