מדרש על בראשית 41:15

And Pharaoh said unto Joseph: I have dreamed a dream, etc. Joseph replied: “God will give Pharaoh an answer” (Gen. 41:15–16). Because He ascribed greatness to Him who possessed greatness, the Holy One, blessed be He, said to him: Since you did not seek to exalt yourself, be assured you will be elevated to greatness and leadership by Me.