The Old Convenant saves no one, because no one could meet its requirements. So whether it's "replaced" or not it irrelevant. It doesn't save.
Only the New Covenant saves people, Jew and Gentile alike.
So then, all the OT saints are in Hell?
Do you even READ your bible?
Let’s say you are a child.
And your Father promises you to take you to get ice cream if you behave.
During the long (to you) day, you really, really do better, but you still do something wrong.
Now, your Father, who saw your effort, BECAUSE YOU HAD FAITH THAT YOUR FATHER WAS A GOOD FATHER AND WOULD REWARD YOU - decides to take you to get ice cream anyway.
Did the child DESERVE ice cream? NO!
Is the Father Good? YES!
Was the child hopeful, and faithful and TRY to fulfill the promise, even though he could not control himself? YES.
This is a picture of Israel - They are saved by FAITH through their belief in the Old Covenant, and Israel is partially blinded to the Savior until the times of the Gentiles are fulfilled.
WHO BLINDED ISRAEL? Did not God know what Israel would do BEFORE He entered into a convent with them? Of course He did. He knows Israel is a “stiff necked” people. Just the type to receive the OT and not change one jot or tittle.
The Covenant does NOT save people. Jesus does. Nothing has changed, our Deliverer has, and always will be, Jesus. Even the New Covenant shows you cannot keep it. Is there a Christian alive who has kept the LAW? Even just the ten commandments? We Christians are in the same boat as the Jews. All must have faith in God to be saved, and it’s Jesus (like it or not) that is the ONLY One that saves.
So then, should we think God made a mistake and has rejected the Jews?
Read Romans 11