John Chrysostom : "And it is yet far more evident, if after the similitude of Melchisedec there ariseth another priest." What is evident? The interval between the two priesthoods, the difference; how much superior He is "who was made not according to the law of a carnal commandment." (Who? Melchisedec? Nay; but Christ.) — Homily on Hebrews 13 Oecumenius : And not only, he says, it is clear from this that the priesthood and the covenant have been changed from that of another tribe, and not from Levi, that the risen priest is from, but also it is evident from this more abundantly. Of which? From that according to the order of Melchizedek, and not according to the former priest Aaron, Christ became a priest. "if according to the likeness of Melchizedek there arises another priest." The "if," instead of "that," you will understand, or rather since; as if he said; And from this it is evident both the change and the transfer of the old covenant. Then according to the likeness. Since, he says, according to the likeness of Melchizedek there arises another priest, and not according to the likeness of Aaron. — The Pseudo-Oecumenian Catena on Hebrews