Matthew 10:30
but the very hairs of your head are all numbered.
WEB
But the very hairs of your head are all numbered.
KJV
What Matthew 10:30 means
Jesus tells his disciples that God's attention to them is so complete that even the hairs of their head are counted, so they have nothing to fear.
Jesus is sending his twelve disciples out to preach, and he has just warned them they will face real hostility. In that setting he points at sparrows: two of them sold for the smallest coin in the market, yet not one falls to the ground without the Father. Then comes the image of the hairs, counted one by one.
The counting is a picture of attention. Nothing about you is too small to be known, including the parts you have never counted yourself. Verse 31 draws the conclusion the whole passage is aiming at: don't be afraid, you are worth more than many sparrows.