R. Yehudah b. Betheirah says: The Holy One Blessed be He said to him: I have already fulfilled My promise to your father Abraham, viz. (Exodus, Ibid. 21) "and He made the sea into the dry land" (that He had promised to Abraham) (Ibid. 29) "and the children of Israel walked in the dry land (that had already been made) in the midst of the sea."