Entering the kingdom of God is to become a citizen or child of God.  Those who are not children of God are not in the kingdom.  Who are the children of God and how can we recognize them?  The Lord recognizes at least two different kinds of children.

Not as though the word of God hath taken none effect. For they are not all Israel, which are of Israel:  Neither, because they are the seed of Abraham, are they all children: but, In Isaac shall thy seed be called.  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  (Rom. 9:6-8).

The Lord discerns between two very different kinds of children—fleshly and spiritual.  Not all of the Israelites were circumcised in heart.  All physical Israel is of Israel physically; however, not all of Jacob’s physical descendants are spiritual children of Israel.  Jesus describes those who are children of Abraham in heart as well as in the flesh. (John 8:37-44).  He acknowledged that the Jews were physically descended from Abraham, as his seed (John 8:37); however, he shows a difference between Abraham’s seed and Abraham’s children.  Jesus acknowledged that the Jews were Abraham’s seed (John 8:37) but denied that they were Abraham’s children.

They answered and said unto him, Abraham is our father. Jesus saith unto them, If ye were Abraham’s children, ye would do the works of Abraham.  But now ye seek to kill me, a man that hath told you the truth, which I have heard of God: this did not Abraham  (John 8:39-40).

Abraham’s children are those who do the works of Abraham.  They walk in the steps of the faith of Abraham.  Only those who walk in Abraham’s steps are his children (Rom. 4:12).  The Jews who had the heart of Abraham could do the works of Abraham (Matt. 12:35).  The Jews (with some exceptions) in Jesus’ time did not have a heart like Abraham.  Their heart was more like the Devil’s heart, because they were seeking to kill God’s Son (John 8:44).  Abraham did not kill the prophets like these Jews were trying to do to Jesus (John 8:40). John the Baptist chided the Jews when he said: “And think not to say within yourselves, We have Abraham to our father: for I say unto you, that God is able of these stones to raise up children unto Abraham” (Matt 3:9).  God could not raise physical children of Abraham out of the stones.  A physical child of Abraham must descend from Abraham’s fleshly body; however, God could easily create “a body” out of stones, and put a soul in that body which had the faith of Abraham (Matt. 3:9) who would do the works of Abraham from “the abundance of a heart” of faith like Abraham.  Unless we do the works of Abraham, we are not children of Abraham.

Similarly, those women who walk in the steps of Sarah, will do the works of faith which Sarah did.  For example: she trusted the One who gave her husband authority over her and obeyed the Lord by obeying Abraham, calling Abraham Lord (1 Pet. 3:6