'Children' in the Bible

an educator of the senseless, a teacher of little children, because you have in the law the essential features of knowledge and of the truth --

The Spirit himself bears witness to our spirit that we are God's children.

And if children, then heirs (namely, heirs of God and also fellow heirs with Christ) -- if indeed we suffer with him so we may also be glorified with him.

that the creation itself will also be set free from the bondage of decay into the glorious freedom of God's children.

nor are all the children Abraham's true descendants; rather "through Isaac will your descendants be counted."

This means it is not the children of the flesh who are the children of God; rather, the children of promise are counted as descendants.

Not only that, but when Rebekah had conceived children by one man, our ancestor Isaac --

And Isaiah cries out on behalf of Israel, "Though the number of the children of Israel are as the sand of the sea, only the remnant will be saved,