God only has one covenant with Man, only one contract that will save him, and it's signed by the blood of Jesus Christ! No one has ever been saved except by the grace of God through Jesus Christ, whether it was before or since Christ's ministry on Earth!
Though many in Old Testament times were saved, nobody was ever saved BY the Old Testament! Nobody was ever saved by keeping the Mosaic Law! Salvation is only by the new Testament, the New Covenant, the Covenant of the blood of Christ! In fact, it is not even new, because He is the Lamb which was slain before the foundation of the Earth! (Rev.13:8) And His Covenant of Grace has been in existence since the World began!--With many looking forward to it. (Heb.11:26,39 and 40) They looked forward to the Saviour of the World, the Son of God, Jesus the Christ. Just as we now look back to His death and victory over sin and the grave, they looked forward to it as God had promised!
Salvation is by faith!--Not by lineage and not by the Law of Moses! It's by pure faith today, and always has been!