Комментарий к Тегилим 110:4

The Lord swore and will not repent Since Abraham was afraid lest he be punished for the troops that he had killed, it was said to him (Gen. 15:1): “Fear not, Abraham, etc.”

and will not repent over the good that He spoke about you.

you are a priest forever because of the speech of Malchizedek From you will emerge the priesthood and the kingship that your children will inherit from Shem your progenitor, the priesthood and the kingship, which were given to him. דִבְרָתִי מלכי-צדק. The “yud” is superfluous, like (Lam. 1:1): “the city that was once so populous (רבתי).” Because of the speech of Malchizedek, because of the command of Malchizedek. You are a priest, Heb. כהן. The word כהן bears the connotation of priesthood and rulership, as (II Sam. 8:18): “and David’s sons were chief officers.”