Exod 11:3

“When Moses had come to the place which God shows him, he is not permitted to ascend, but first God says to him, "Loose the tie of the shoes from your feet." None of these things are said to Abraham and Isaac, but they ascend and do not put aside their shoes. The reason for this is perhaps that although Moses was "great," he was nevertheless coming from Egypt, and some fetters of mortality were bound to his feet. Abraham and Isaac, however, have none of these, but "they come to the place."”

“About Isaac it is said that "he grew strong until he became great, exceedingly great." Moses was called "great," and John the Baptist was called "great," and now Jesus is called "great," and after this no one is any longer called "great." For before he who is truly "great" had come, in comparison with the rest of men, the saints whom we mentioned earlier were called "great."”