'Promise' in the Bible

For the promise, that he should be the heir of the world, was not to Abraham, or to his seed, through the law, but through the righteousness of faith.

For if they which are of the law be heirs, faith is made void, and the promise made of none effect:

Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all,

so that the promise should be made sure to all Abraham's true descendants; not merely to those who are righteous through the Law, but to those who are righteous through a faith like that of Abraham. Thus in the sight of God in whom he believed, who gives life to the dead and makes reference to things that do not exist, as though they did, Abraham is the forefather of all of us. As it is written, "I have appointed you to be the forefather of many nations."

He staggered not at the promise of God through unbelief; but was strong in faith, giving glory to God;

and being absolutely certain that whatever promise He is bound by He is able also to make good.

and they are not all the children of Abraham because they are his descendants [by blood], but [the promise was]: “Your descendants will be named through Isaac” [though Abraham had other sons].

That is, They which are the children of the flesh, these are not the children of God: but the children of the promise are counted for the seed.

For this is the word of promise, At this time will I come, and Sara shall have a son.