Old Testament

The Book of Genesis: Chapter 17:9-14

 And God said to Abraham: "As for you, you shall keep My covenant, you and your descendants after you throughout their generations. This is My covenant which you shall keep, between Me and you and your descendants after you: Every male child among you shall be circumcised; and you shall be circumcised in the flesh of your foreskins, and it shall be a sign of the covenant between Me and you. He who is eight days old among you shall be circumcised, every male child in your generations, he who is born in your house or bought with money from any foreigner who is not your descendant. He who is born in your house and he who is bought with your money must be circumcised, and My covenant shall be in your flesh for an everlasting covenant. And the uncircumcised male child, who is not circumcised in the flesh of his foreskin, that person shall be cut off from his people; he has broken My covenant."

New Testament (New King James Version)

The Gospel According to John: Chapter 6:60-71

Therefore many of His disciples, when they heard this, said, "This is a hard saying; who can understand it?" When Jesus knew in Himself that His disciples complained about this, He said to them, "Does this offend you? What then if you should see the Son of Man ascend where He was before? It is the Spirit who gives life; the flesh profits nothing. The words that I speak to you are spirit, and they are life. But there are some of you who do not believe." For Jesus knew from the beginning who they were who did not believe, and who would betray Him. And He said, "Therefore I have said to you that no one can come to Me unless it has been granted to him by My Father." From that time many of His disciples went back and walked with Him no more. Then Jesus said to the twelve, "Do you also want to go away?" But Simon Peter answered Him, "Lord, to whom shall we go? You have the words of eternal life. Also we have come to believe and know that You are the Christ, the Son of the living God." Jesus answered them, "Did I not choose you, the twelve, and one of you is a devil?" He spoke of Judas Iscariot, the son of Simon, for it was he who would betray Him, being one of the twelve.