God doesn't need to fulfill His promise? That's certainly an odd thing to say.
He did in the original sense; several places in Joshua say so.
But we also read in the NT (Heb 11) that they weren't looking for a land there anyway, even when they got to Judea. Rom 4 says the inheritance of Abraham along with us is the 'world to come.' The NHNE.
The question is whether exilic prophecy like Isaiah's 2nd half, or Dan 8-9, is saying that a redemptive Messiah is coming (for sure on that one) and ALSO that the same land promise as back in Gen 12 is also going to be delivered all over again. There is nothing about that in the NT, instead, it dwells on the mission. Because of things Isaiah said: 'It is too small thing for you (the Servant) to restore the fortunes of Israel; I will make you a light to the nations.' Or Dan 9's showing us that while Messiah succeeds in his work, Israel is desolated, at the same time.