Judaism G-d Relationship with Israel

[nili]

In Deuteronomy 17:15, God does say: "You shall set a king over you."  He also says that the king must be one who is chosen by God.  Then, much later on, in I Samuel 8:7, when the people are clamoring for a king to judge them, God tells his prophet Samuel:  "Listen to the voice of the people, according to all that they will say to you, for they have not rejected you, but they have rejected Me from reigning over them." 

Out of curiosity, who do you suppose authored these two quotes and when?