I am not an expert in Jewish stuff, but yes. God did make that covenant.
According to LDS beliefs when Jesus came, he brought a new and higher covenant with Him.
In no way whatsoever is it saying the old one was wrong. It actually agrees wholly with the new one Jesus brought.
ANY covenant is accepted on a personal level. That includes baptism and baptism for the dead.
According to the new covenant one MUST be baptised, ala make the covenant that Jesus brought.
Mormons believe that everyone will have a fair chance to learn what God REALLY wants either now or later. If someone never had the chance to learn about God, they will be able to have that chance later on.
Because baptism is required thats why we do baptism for the dead. If the person who one is baptised for refuses the ordinance or covenant, there is nothing anyone can do about it.
Conversion is a spiritual thing, not a temporal thing, ala baptism only.
God has to be fair though. He is fair and completely just. Hence everyone has to have the chance to accept or reject the message.
Baptism for the dead is NOT accepting Jesus on behalf of another person.
And that's really the crux of the whole debate. Perhaps Orthodox Judaism doesn't see it this way but most other religions believe that God desires all men to find salvation through their religion. And yet it's impossible to think that everyone in every tribe throughout the world has had a chance to be informed and to make a choice. Our sense of fairness tells us it is not fair for a just God to condemn a soul that never got the chance to accept salvation.
The Christians have a rather lame yet Scripture-based logic that says God is so obvious to mankind that man naturally seeks after God and will surely find Him if they seek him. But does that mean the path to salvation is obvious? Probably not. And yet He commands His disciples to go spread the message to every corner of the globe.
But what of those who die as infants? What of the aborted?What of those who live in such backwater villages that the Plan never reaches their ears? What of those who are mentally retarded or those with learning disabilities? It's not realistic for everyone to be reached or to understand well enough to decide.
What the Mormons (IMO) are attempting to do is bridge this gap using baptism by proxy. The Mormon answer to this dilemma is to write a really really really long list of everybody whose name they can find and then offer them a shot at salvation.
Beats me if that's okay with God but if the Mormons believe it, who am I to object? They're only trying to save souls in the most efficient way possible and that ought to be a good thing.
It's all part of that bigger "free will vs predestination" debate that will probably never be understood until we leave our finite carcasses and move on to a new world with new understandings.
Yeah... the prophet Jeremiah had something to say along that line.........