I lay down and slept; I awoke, for the Lord sustained me.
Psalms 3:5 (NKJV)

I will both lie down in peace, and sleep; for You alone, O Lord, make me dwell in safety.
Psalms 4:8 (NKJV)

When you lie down, you will not be afraid; yes, you will lie down and your sleep will be sweet.
Proverbs 3:24 (NKJV)