What were the Jews in John 8 relying on when they argued with Jesus?
They relied on their physical genealogy as descendants of Abraham, Isaac, and Jacob, assuming that heritage guaranteed a right standing before God. Even though they possessed the Scriptures, the Word of God, and the priesthood, they remained wrapped in unbelief and could not comprehend Jesus' words.
Les explains that the Jews in John 8 were relying on their genealogy—being the children of Abraham, Isaac, and Jacob. They had unique opportunities: the Scriptures, the Word of God, and the priesthood. Yet they were wrapped in unbelief and could not comprehend. When Jesus told them the truth, they accused Him of being a Samaritan and having a demon. Les then connects this to Romans, verse 16: 'So then it is not of him that willeth.' A person cannot claim a right standing with God simply because of genealogy, nationality, or race.
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.