'Sons' in the Bible

Be certain, then, that those who are of faith, the same are sons of Abraham.

Because you are all sons of God through faith in Christ Jesus.

That he might make them free who were under the law, and that we might be given the place of sons.

And because you are sons, God has sent out the Spirit of his Son into our hearts, saying, Abba, Father.

Because it is in the Writings, that Abraham had two sons, one by the servant-woman, and one by the free woman.