'Children' in the Bible

The Spirit himself doth testify with our spirit, that we are children of God;

and if children, also heirs, heirs, indeed, of God, and heirs together of Christ -- if, indeed, we suffer together, that we may also be glorified together.

that also the creation itself shall be set free from the servitude of the corruption to the liberty of the glory of the children of God;

nor because they are seed of Abraham are all children, but -- 'in Isaac shall a seed be called to thee;'

that is, the children of the flesh -- these are not children of God; but the children of the promise are reckoned for seed;