This idiom means that Abraham trusted God even though it did not seem that he could have a son. AT: "Even though it seemed impossible for him to have descendants, he believe God" (See: [[rc://en/ta/man/translate/figs-explicit]])
The full promise God gave to Abraham can be made explicit. AT: "You will have more descendants than you can count" (See: [[rc://en/ta/man/translate/figs-explicit]])