Expository Notes of Dr. Thomas Constable - Genesis 17
7. The sign of circumcision ch. 17The Lord confirmed His covenant with Abram, 13 years after Ishmael’s birth, by reiterating the promises of descendants and land and by commanding Abram to circumcise all the males in his household. Circumcision thereby became the physical demonstration (sign) of the obedient faith of Abram and his descendants. There are three types of signs in the Old Testament. Some signs were proofs that convinced observers of something (e.g., the Egyptian plagues). Others... read more
Commentary Critical and Explanatory on the Whole Bible - Genesis 17:19
19, 20. The blessings of the covenant are reserved for Isaac, but common blessings were abundantly promised to Ishmael; and though the visible Church did not descend from his family, yet personally he might, and it is to be hoped did, enjoy its benefits. read more