For his anger endureth but a moment; in his favour is life: weeping may endure for a night, but joy cometh in the morning.
Psalms 30:5
Again and again, the scriptures link repentance to joy. Here is another beautiful example.
I also like this scripture because everything seems to look better in the morning. When I am burdened and sad at night, I try to remind myself that after some rest, I will be able to see solutions more clearly.
I read a book this year about the science behind sleep. There is real, restorative work that happens in our brains as we sleep. What a blessing from God.