Psalm 16:7 (NIV) I will praise the LORD, who counsels me; even at night my heart instructs me.
Our heart oft times wakes when we sleep, and God can speak to that, either by words, by proverbs, by signs and similitudes, as well as if one was awake. - John Bunyan (1628-1688)
Edythe Draper, Draper's Book of Quotations for the Christian World, (Wheaton, IL: Tyndale House Publishers, 1992), WORDsearch CROSS e-book, Under: "Dreams".