you knitted me together in my mother's womb.
I praise you, for I am fearfully and wonderfully made.
Wonderful are your works;
my soul knows it very well.
My frame was not hidden from you,
when I was being made in secret,
intricately woven in the depths of the earth.
Your eyes saw my unformed substance;
in your book were written, every one of them,
the days that were formed for me,
when as yet there were none of them.
Psalms 139:13-16 (ESV)
If you drew hard theology from this passage, you might make some conclusions about predestination and free will. But this is a poem. A song. That's what a Psalm is. It's not the best place to determine the specific workings of the spiritual. It is, however, the perfect place to learn to worship.
Sometimes God makes right turns. We think we know exactly where He's headed, and the path He'll take us along to get there. One thing you learn quickly when you try to follow God is that He loves off-roading.
Even though He's God, it's really easy to get annoyed at Him. To doubt Him. We get awfully attached to our own visions of our own lives, and when He - politely or not - informs us that He has a different vision, we tend to get up in arms.
In Psalm 139, David recognizes what we so readily forget. A simple fact that changes everything when we actually believe it.
God loves us, and He knows what He's doing.