Verses with the word nights in the Old Testament (15 verses):

Genesis 7:4
For yet seven days, and I will cause it to rain upon the earth forty days and forty nights; and every living substance that I have made will I destroy from off the face of the earth.

Genesis 7:12
And the rain was upon the earth forty days and forty nights.

Exodus 24:18
And Moses went into the midst of the cloud, and gat him up into the mount: and Moses was in the mount forty days and forty nights.

Exodus 34:28
And he was there with the LORD forty days and forty nights; he did neither eat bread, nor drink water. And he wrote upon the tables the words of the covenant, the ten commandments.

Deuteronomy 9:9
When I was gone up into the mount to receive the tables of stone, even the tables of the covenant which the LORD made with you, then I abode in the mount forty days and forty nights, I neither did eat bread nor drink water:

Deuteronomy 9:11
And it came to pass at the end of forty days and forty nights, that the LORD gave me the two tables of stone, even the tables of the covenant.

Deuteronomy 9:18
And I fell down before the LORD, as at the first, forty days and forty nights: I did neither eat bread, nor drink water, because of all your sins which ye sinned, in doing wickedly in the sight of the LORD, to provoke him to anger.

Deuteronomy 9:25
Thus I fell down before the LORD forty days and forty nights, as I fell down at the first; because the LORD had said he would destroy you.

Deuteronomy 10:10
And I stayed in the mount, according to the first time, forty days and forty nights; and the LORD hearkened unto me at that time also, and the LORD would not destroy thee.

1 Samuel 30:12
And they gave him a piece of a cake of figs, and two clusters of raisins: and when he had eaten, his spirit came again to him: for he had eaten no bread, nor drunk any water, three days and three nights.

1 Kings 19:8
And he arose, and did eat and drink, and went in the strength of that meat forty days and forty nights unto Horeb the mount of God.

Job 2:13
So they sat down with him upon the ground seven days and seven nights, and none spake a word unto him: for they saw that his grief was very great.

Job 7:3
So am I made to possess months of vanity, and wearisome nights are appointed to me.

Isaiah 21:8
And he cried, A lion: My lord, I stand continually upon the watchtower in the daytime, and I am set in my ward whole nights:

Jonah 1:17
Now the LORD had prepared a great fish to swallow up Jonah. And Jonah was in the belly of the fish three days and three nights.