David marvels at the wonder of God's total knowledge of him — God knows when he sits and rises, every word before he speaks it, and His presence fills every place. There is nowhere David can go that God is not there. God formed David in his mother's womb with care and skill. David is fearfully and wonderfully made. He ends by asking God to search and know his heart.
God knows everything about you — every thought, every word, every part of how He made you — and He loves what He made. You are not an accident. You were carefully and wonderfully made by God, and He knows you completely.
Psalm 139 is perhaps the most intimate psalm in the Psalter — a meditation on God's omniscience and omnipresence not as threats but as comforts. For children this psalm is formative in two ways: (1) identity — 'You are known, seen, and made with care' (v13-16 are crucial for children's self-understanding in a world that often makes them feel insignificant); (2) security — 'There is nowhere I can go where God is not' (v7-12 answer fear of abandonment). Note that the 'fearfully' in v14 means 'with reverence and awe' — God made humans as His most remarkable work. Verse 23-24 is a model prayer of self-examination: David invites God to search and know him, not as a threat but as an act of trust. For children: focus on vv1-6 (God knows me), vv13-14 (God made me), and vv23-24 (I can trust God with my whole heart).
God knows your name, your thoughts, your favourite things — He knows everything about you and He LOVES you! You are not an accident. God made you carefully and wonderfully, and there is nowhere you can go where God is not right there with you.