Peter's two descriptions in Mt 16.13-23

Q.Why is Peter called "blessed "and then it seems he is called "Satan" in Mt 16.13-23?
A. The verses being referred to can be puzzling, but we need to see these verses as they would have in the 1st century. Yeshua is asking what the people are saying about him. He is in the north near Caesarea Phillipi. His talmidim begin to say what they have heard. He then asks them what they think, and Peter says He is the Messiah, the Son of the Living G-d. Yeshua then says that Peter is blessed for knowing that and that this revelation will be what the eschatological congregation will be built upon, and the gates of hell will not prevail against it. Now it is interesting that in the area where they were, there was a cave that the pagans believed was the gates of hell, dedicated to the pagan g-d Pan.

So He drew on what the local belief was to illustrate His point here. In v 21 Yeshua goes on to say how He must go to Jerusalem and be killed. So, Peter again stands up and says that this should not happen. It is then that Yeshua says"get thee behind me Satan, thou art an offense to me". Why did Yeshua say this? In the 1 st century there was a well known "midrash" or story about Abraham. In Gen 22 we have the story of the Akeida, or the binding of Isaac. Isaac was aroung 33 years old when this happened, not a young boy as has been depicted. He goes to Jerusalem, called Salem then, to the land of Moriah and is told to sacrifice Isaac. As Abraham is going, Satan tries to stop him by creating a river to drown them both. Realizing this, Abraham says "get thee behind me Satan" and the river disappears and they both go on to Moriah. In Mt 16, it is the same scenario. The father is going to Moraih to sacrifice His Son Yeshua.

Yeshua is the same age as Isaac, going to the same place. The story in Gen 22 is an obvious picture of what Yeshua will do in the future. Just as Satan tried to thwart Abraham in the midrash, Peter says no to Yeshua's task, thus putting himself in the role of Satan. So, when Yeshau uses the phrase "get thee behind me Satan" he was drawing an obvious parallel between the midrash on Gen 22 and what Peter was saying in trying to hinder His trip to Jerusalem. By using thes words, Yeshua was making this connection between what Abraham did and what He was going to do, and saying that Peter was opposing the things of G-d. He was not actually calling Peter "Satan" but saying that the power behind such statements are from the evil one.