I didnt watch the video yet. I dont want it to interfere with my translation.
I'm pretty sure that in Psalm 139, David was lamenting his disobedience to the Lord with that Bathsheba incident.
Psalm 139:
14 I will praise thee; for I am fearfully and wonderfully made: marvellous are thy works; and that my soul knoweth right well.
15 My substance was not hid from thee, when I was made in secret, and curiously wrought in the lowest parts of the earth.
16 Thine eyes did see my substance, yet being unperfect; and in thy book all my members were written, which in continuance were fashioned, when as yet there was none of them.../KJV
David felt like hiding from the Lord, but he realized the futility of it. God is omniciscient, everywhere at once and at all times. So if he went to the mountain, God is there. If to sheol, God is there too. God created us so He knows us better than we know ourselves. We know we are as of yet, unperfected and that there is no hiding from God. So David turned to the Lord in repentance for his sins...and he never did that again!
v16 simply says David knows God knew exactly how he would be before he was even ever born on earth.
In most cases when we sin, not only do we ask forgiveness for it, but we ask, Lord, why did I do that? That is not my heart!