Herod, a Jewish convert and non-Israeli is appointed King of the Jews.   He is anxious about his position. We know this. So, he stacks the Sanhedrin with his own relatives or people who come from his homeland.
They say they are children of Abraham as a means of establishing their social  and religious authority. They do not say they are children of Jacob. Children of Abraham are not necessarily children of Jacob. But, children of Jacob are certainly children and  descendants of Abraham. What do you say instinctually or in argument to establish your social authority?  If you are Abraham's children, then you should do as Abraham did. He lived in relationship to the Spirit; not by a letter code only or the misunderstanding of a code. See the Pikuach nefesh and read Mark 3.  Jesus said be born again to live by the Spirit of Life as did Abraham; the Spirit of life that manifests in the word  and commands of God where your ego is subsumed by God's mind, intentions and spirit. This is the call to the children of Abraham.   All the same, everyone is related to Yeshua through Eve (Yasha (Hebrew) or Haya).  The message is that you are innately accepted in the manner and method that God made you! No one is  less loved or accepted in the deliverance claimed by Eve(Haya) after the birth of Seth and represented in his son, Yeshua(the Christ) who is born of a woman and immaculately conceived.    Everyone has a calling and gift that will ignite to salvation in trusting God's word.  Be patient as you grow. Do not join the devil in condemning yourself  in the event that you should you stumble.