Ephesians 3:16

That according to the riches of his glory he may grant you to be strengthened with power through his Spirit in your inner being,

2 Corinthians 4:16

So we do not lose heart. Though our outer self is wasting away, our inner self is being renewed day by day.

1 Peter 3:4

But let your adorning be the hidden person of the heart with the imperishable beauty of a gentle and quiet spirit, which in God's sight is very precious.