How were people between Abraham and Paul saved?
Between Abraham and Paul, salvation required faith plus works. Scripture indicates they were not saved by faith alone as Abraham was, but by believing God and adding prescribed sacrifices, law-keeping, repentance, and baptism as required. This contrasts with Paul's gospel of faith plus nothing.
Les explains that John the Baptist began preaching to Israel with the keeping of the law, the bringing of the prescribed sacrifice, and a salvation experience that included repentance and water baptism. During that period, it was faith plus sacrifice, works, or whatever was added. Then Paul comes and says it is faith plus nothing, tying believers to Abraham, who was saved by faith plus nothing. Everyone in between was saved by faith plus works, while Abraham's spiritual seed comes by faith plus nothing and his physical relationship was with the nation of Israel.