What does Genesis 17:23 mean?
Abraham immediately demonstrates his faith in the God who appeared to him by obeying God's command. Abraham kept his part of the covenant God had initiated by circumcising himself and every male in his extensive household. He did so on the very day God appeared to him, starting with Ishmael, his 13-year-old son.Circumcision was not unheard of in that era, but this does not change the magnitude of Abraham's immediate obedience. Circumcision involves removing the foreskin from the penis, which is painful and, one would assume, awkward. We're not told anything of the reaction to Abraham's requirement for all the men and boys under his care. Abraham overcame whatever resistance may have presented itself to obey the command of the Lord. It's worth noting that those who would have resisted this command entirely had an option, of sorts: to be "cut off," or separated, from the family of Abraham (Genesis 17:14).