'Posterity' in the Bible

"You are the heirs of the Prophets, and of the Covenant which God made with your forefathers when He said to Abraham, 'And through your posterity all the families of the world shall be blessed.'

But he gave him no inheritance in it, no, not a single square yard of ground. And yet He promised to bestow the land as a permanent possession on him and his posterity after him--and promised this at a time when Abraham was childless.

And God declared that Abraham's posterity should for four hundred years make their home in a country not their own, and be reduced to slavery and be oppressed.

In His humiliation justice was denied Him. Who will make known His posterity? For He is destroyed from among men."