Matthew 16:23

Verse 23. Get thee behind me, Satan. The word Satan means, literally, an adversary, or one that opposes us in the accomplishment of our designs. It is applied to the devil commonly, as the opposer or adversary of man. But there is no evidence that the Lord Jesus meant to apply this term to Peter, as signifying that he was Satan or the devil, or that he used the term in anger. He may have used it in the general sense which the word bore, as an adversary or opposer; and the meaning may be, that such sentiments as Peter expressed then were opposed to him and his plans. His interference was improper. His views and feelings stood in the way of the accomplishment of the Saviour's designs.