Why could Christ not have preached the Gospel to Abraham?
The Gospel of the death, burial, and resurrection as the means of salvation was not revealed in Abraham's day. No reference to that message appears between Abraham and Paul, and Abraham knew nothing of Roman crucifixion. Scripture preached justification by faith to Abraham, not the Gospel.
Les explains that this passage is a matter of emphasis. If you emphasize the word "Gospel," you wrongly conclude that Christ preached the Gospel to Abraham. But the Scripture, foreseeing that God would justify the non-Jew by faith, preached justification to Abraham, not the Gospel. Abraham had no idea of a Roman crucifixion, and nobody back then knew what crucifixion was. If the Gospel had been preached to Abraham, then somewhere between Abraham and Paul there would have been some reference to the death, burial, and resurrection as a means of salvation, but there is not. Searching the four Gospels also shows no one was told to be saved by believing Jesus died for the sins of the world, was buried, and rose from the dead. Les says we have no right to push it back there; we leave everything where it sits. The two words "but now" in Ephesians 2:13 show that it has not always been that way.