But as of one (all w ep eno). But as in the case of one. Which is Christ (o estin Cristo). Masculine relative agreeing with Cristo though sperma is neuter. But the promise to Abraham uses sperma as a collective substantive and applies to all believers (both Jews and Gentiles) as Paul has shown in verses Hebrews 7-14 , and as of course he knew full well Here Paul uses a rabbinical refinement which is yet intelligible. The people of Israel were a type of the Messiah and he gathers up the promise in its special application to Christ. He does not say that Christ is specifically referred to in Genesis 13:15 or Genesis 17:7 .