Even before a word is on my tongue, You know all about it, O LORD.
For there is not a word in my tongue, but lo, O Lord, thou knowest it altogether. The unformed word, which lies within the tongue like a seed in the soil, is certainly and completely known to the Great Searcher of hearts.
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
Thou hast beset me behind and before,.... Art on every side of me, all around me, like one besieged in a strait place; so that there is nothing I can think, say, or do, but what is known unto thee.