11:17–19 The ultimate test of Abraham’s faith was the sacrifice of Isaac. Isaac was the “only son” (cf. John 3:16) so far as the promises were concerned (v. 19)—neither Abraham’s servant Eliezer (Gen. 15:2) nor his other son Ishmael (Gen. 17:20, 21) would do. If Isaac were to perish without offspring, the promises of God would fail. Abraham’s readiness to slay the son of promise at God’s command could arise from nothing less than the conviction that “God was able even to raise . . . the dead” (v. 19). Isaac’s “resurrection” was only figurative, but believers who have died for their faith look forward to a literal resurrection (cf. v. 35), in which Jesus has led the way (13:20).