Your eyes saw my unformed body; all my days were written in Your book and ordained for me before one of them came to be.
The Potter saw the vessel while yet on the wheel, unperfect and unformed. God's knowledge is no hearsay, He observes with intent and certainty as a man sees with his eyes. Before a single member existed, all were written in His book of purposes, their form and faculties appointed in the secret decree.
AI summary
David refuses the hiding places where men cloak themselves in lies. He fixes on a truth that strips all pretense bare: nothing escapes God's sight, not because He watches from afar, but because He shaped us bone by bone in darkness and cannot be ignorant of what He has made.
AI summary
Commenting on Psalm 139:1-24
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. (l) Seeing that you knew me before I was composed of either flesh or bone, much more now must you know me when you have fashioned me.