'Fulfilment' in the Bible

For if the inheritance comes through obedience to Law, it no longer comes because of a promise. But, as a matter of fact, God has granted it to Abraham in fulfilment of a promise.

And if you belong to Christ, then you are indeed true descendants of Abraham, and are heirs in fulfilment of the promise.

But we see that the child of the slave-girl was born in the common course of nature; but the child of the free woman in fulfilment of the promise.

But you, brethren, like Isaac, are children born in fulfilment of a promise.