For when God made promise to Abraham,.... The apostle proposes Abraham as a pattern, because he was the father of these Hebrews, and of all believers; and because they were interested in the promise made to him, and had a right to the same blessing with him; and because he was remarkable for his faith and patience: the promise made to him is not that in Ge 12:1 nor that in Ge 15:1 but that in Ge 22:16 for that only had an oath annexed to it: and this was made by Jesus Christ, there called the Angel of the Lord, and here God; and who is truly and properly so; and than whom there is none greater; and who elsewhere, as here, is said to swear by himself, Isa 45:23 as follows:because he could swear by no greater, he sware by himself; swearing is ascribed to a divine person after the manner of men, and in condescension to them; and who is never introduced swearing, but in matters of moment and of great importance; the note of Philo the Jew on the passage in Ge 22:16 from whence the following words are cited, is worthy of observation, being very near the apostle's words;"well does he (God) confirm the promise with an oath, and with an oath that becomes God; for you see that God does not swear by another, for nothing is better than himself, but by himself, who is the best of all; but some have suggested as if it was inconvenient to swear, for an oath is taken for the sake of faith; but God alone is faithful, &c.'
' Leg. Allegor. l. 2. p.