In peace I will lie down and sleep,
for you alone, LORD,
make me dwell in safety.
(Psalm 4:8)

This is one of those short and easy to memorize scriptures that provides comfort in tough times.  I think our mind focuses on our troubles more at bedtime and keeps us from relaxing and finding sleep.  Keep this scripture tucked away for troubled nights and it will help settle your mind and bring peace and rest.