Christians do not practise circumcision because it was not a commandment from Lord YaHshua Messiah. Some Christians are circumcised for hygienic grounds but not on religious grounds.
The issue on whether or not Circumcision is a pre-requisite for Christians to be part of the Abrahamic Convenant, had been debated and resolved in the first century AD. Apostle Simon Peter related his vision as to how YHWH God told him to baptize the Gentiles Messianics or uncircumcised persons.
Act 10:44 And while Simon was uttering these things, the Holy Spirit overshadowed all them that were hearing the word.
Act 10:45 And the circumcised brethren who came with him, were amazed and astonished, that the gift of the Holy Spirit was poured out upon the Gentiles also.
Act 10:46 For they heard them speak with diverse tongues, and magnify God.
Act 10:47 And Simon said: Can any one forbid water, that those should not be baptized, they who have received, lo, the Holy Spirit, as well as we?
Act 10:48 Then he commanded them to be baptized in the name of our Lord Jesus Messiah. And they requested him to remain with them [some] days.
Act 11:1 And it was reported to the legates and the brethren in Judaea, that the Gentiles also had received the Word of God.
Act 11:2 And when Simon went up to Jerusalem, they who were of the circumcision contended with him,
Act 11:3 saying; that he had gone in to be with uncircumcised persons, and had eaten with them.
Act 11:4 And Simon began to address them methodically:
Act 11:5 As I was in Joppa, praying, I saw in vision, that a certain vessel descended, which was like a sheet, and it was tied at its four corners; and it descended from heaven and came to me.
Act 11:6 And I looked upon it, and I saw that in it were fourfooted animals, and reptiles of the earth, and fowls of heaven.
Act 11:7 And I heard a voice, which said to me: Simon, arise slay and eat.
Act 11:8 And I said: Far be it, my Lord. For never hath any thing polluted or unclean entered my mouth.
Act 11:9 And again, a voice from heaven said to me: What God hath cleansed, make thou not unclean.
Act 11:10 And this was done three times: and the whole was taken up to heaven.
Act 11:11 And at the same instant, three men, who were sent to me by Cornelius from Caesarea, came and stood at the gate of the court where I lodged.
Act 11:12 And the Spirit said to me: Go with them, without hesitation. And these six brethren went also with me, and we entered the man's house.
Act 11:13 And he related to us, how he had seen an angel in his house, who stood and said to him: Send to the city of Joppa, and bring Simon who is called Cephas;
Act 11:14 and he will utter to thee discourses, by which thou wilt live, thou and all thy house.
Act 11:15 And when I there commenced speaking, the Holy Spirit overshadowed them, as it did us from the beginning.
Act 11:16 And I remembered the word of our Lord, when he said: John baptized with water, but ye shall be baptized with the Holy Spirit.
Act 11:17 If then God equally gave the gift to the Gentiles that believed in our Lord Jesus Messiah, as he did to us: who was I, that I could forbid God?
Act 11:18 And when they heard these words, they desisted; and they glorified God and said: Now to the Gentiles also doth God give repentance unto life.
Circumcision Issue was debated in Jerusalem amongst the Apostles of Yahushua Messiah and the Consensus Drawn
Act 15:5 And some who from the sect of the Pharisees had believed, rose up and said: It is necessary for you to CIRCUMCISE them, and to command them to observe the law of Moses.
Act 15:6 And the legates and Elders assembled, to look into this matter.
Act 15:7 And when there had been much discussion, Simon arose and said to them: Men, brethren, ye know that, from the earlier days, God chose that from my mouth the Gentiles should hear the word of the gospel, and should believe.
Act 15:8 And God, who knoweth what is in hearts, bore testimony concerning them, and gave the Holy Spirit to them, even as to us.
Act 15:9 And he made no distinction between them and us; because he purified their hearts by faith.
Act 15:10 And now, why tempt ye God, by putting a yoke on the necks of the disciples, which neither our fathers nor we could bear?
Act 15:11 But we believe, that we as well as they, are to have life by the grace of our Lord Jesus Messiah.
Act 15:12 And the whole assembly were silent, and listened to Paul and Barnabas, who related how God by their hands had wrought signs and prodigies among the Gentiles.
Act 15:13 And after they ceased, James arose and said: Men, brethren, hearken to me.
Act 15:14 Simon hath related to you, how God hath begun to elect a people for his name from among the Gentiles.
Act 15:15 And with this the words of the prophets accord, as it is written:
Act 15:16 After these things I will return, and will set up the tabernacle of David that had fallen; and will build that which was in ruins in it, and will raise it up:
Act 15:17 so that the residue of men may seek the Lord, and all the nations on whom my name is called; saith the Lord, who doth all these things.
Act 15:18 Known, from of old, are the works of God.
Act 15:19 Therefore I say to you, let them not crush those who from among the Gentiles have turned unto God.
Act 15:20 But let word be sent to them, that they keep aloof from the defilement of a sacrifice [to idols], and from whoredom, and from what is strangled, and from blood.
Act 15:21 For in every city, from former ages, Moses hath heralds in the synagogues, who read him every sabbath.
Act 15:22 Then the legates and Elders, with all the church, chose men from among themselves, and sent them to Antioch, with Paul and Barnabas; [namely], Jude, who was called Barsabas, and Silas, men who were chiefs among the brethren.
Act 15:23 And they wrote a letter by them, thus: The legates and Elders and brethren, to them that are in Antioch, and in Syria, and in Cilicia, brethren who are from the Gentiles, greeting:
Act 15:24 We have heard, that some have gone from us and disquieted you, by discourses, and have subverted your minds, by saying, That ye must be circumcised and keep the law; things which we have not commanded them.
Act 15:25 Therefore we all have thought fit, when assembled, to choose and send men to you, with our beloved Paul and Barnabas,
Act 15:26 men who have given up their lives for the name of our Lord Jesus Messiah.
Act 15:27 And we have sent with them Jude and Silas, that they may tell you the same things orally.
Act 15:28 For it was pleasing to the Holy Spirit, and to us, that there should not be laid upon you any additional burden, besides these necessary things:
Act 15:29 that ye keep aloof from a sacrifice [to idols], and from blood, and from what is strangled, and from whoredom. And if ye keep yourselves from these, ye will do well. Be ye steadfast in the Lord.
Act 15:30 And they who were sent, came to Antioch, and assembled all the people, and delivered the letter.
Act 15:31 And when they had read [it], they rejoiced and were comforted.
Is the Circumcision Superior than Uncircumcised?
1Cor 7:18 Is any man called being circumcised? let him not become uncircumcised. Is any called in uncircumcision? let him not be circumcised.
1Cor 7:19 Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of YHWH.
1Cor 7:20 Let every man abide in the same calling wherein he was called.
Lord Yah'shua Messiah personally called for all to be baptized by His Holy Spirit and with water, and nothing about circumcision.
John 3:5 Jesus replied, and said to him "Verily, verily, I say to thee, That, unless a man be born of water and the Spirit, he cannot enter the kingdom of God."
Mark 16:15 And he said to them: Go ye into all the world, and proclaim my tidings in the whole creation.
Mark 16:16 He that believeth, and is baptized, liveth; but he that believeth not, is condemned.
Act 1:4 And when He (YaHshua) had eaten bread with them, he instructed them not to depart from Jerusalem, but to wait for the promise of the Father, which (said he) ye have heard from me.
Act 1:5 For John baptized with water; but ye will be baptized with the Holy Spirit after not many days.
Why YaHushua was baptized if the Law of Circumcision ceased until John the Baptist?
Matt 11:13 YaHshua said "For all the prophets and the law prophesied, until the time of John."
Luke 16:16 "The law and the prophets were until John: since then, the kingdom of God is proclaimed, and every one presseth it to enter in.
Luke 16:17 And it is easier for heaven and earth to pass away, than for one letter to pass from the law."
As a matter of fact YaHshua came BEFORE John the Baptist according to the words of Prophet John the Baptist. Although YaHshua began His ministry about 6 months later than John, the existence of YaHshua was even earlier than Abraham. So who say YaHshua exist later than John???
Three (3) Times, Prophet John declared that Yahushua was BEFORE him.
John 1:15 John testified of him, and cried, and said: This is He, of whom I said, That he cometh after me, and is BEFORE me; for he was prior to me.
John 1:26 John answered, and said to them; I baptize with water; but among you standeth one, whom ye do not know.
John 1:27 He it is that cometh after me, and was BEFORE me, whose shoe-strings I am not worthy to untie.
John 1:29 The day after, John saw Jesus coming towards him, and said: Behold, the Lamb of God, that beareth the sin of the world.
John 1:30 This is he of whom I said, After me cometh a man, who is BEFORE me, for he was prior to me.
YaHshua declared that He existed BEFORE Abraham:
John 8:57 The Jews say to him: Thou art not yet fifty years old, and hast thou seen Abraham?
John 8:58 Jesus said to them: Verily, verily I say to you, That before Abraham existed, I was.
YaHshua had to fulfill all the prophecies spoken by the Prophets before Him.
John 19:28 After these things, Jesus knew that every thing was finished; and, that the scripture might be fulfilled, he said: I thirst.
BUT YaHshua was not physically circumcised because He is the Son of YHWH God. The scripture says He was named YAHSHUA on the 8th day which is the Circumcision Day but it does not say He was circumcised on the 8th Day from birth.
Luke 2:21 And when the eight days for the circumcision of the child were completed, His Name was called YAHUSHUA; as He was named by the angel, before He was conceived in the womb.
External Sources or About the Circumcision of Yahshua
Book of the Cave of Treasure
[The Circumcision of Christ.]
Now Christ was eight days old when the Magi presented their offerings; and Mary received them at the very time when Joseph circumcised Christ. In truth, Joseph circumcised Him according to the Law, but he only went through (or imitated) the act of cutting, for no [flesh] whatsoever was cut off from Him. For as [a rod of] iron passeth through the fire and cutteth the rays thereof, without any part of it being cut off from it, so in like manner was Christ circumcised without anything being taken from Him.
[The Conversion of the Magi.]
And the Magi lived with the Child three days, and they saw the hosts of heaven going up and coming down to Christ. And they heard the sound of the praises of the angels, who sang hymns and cried out, "Holy, Holy, Holy, Mighty God, with whose praises the heavens and the earth are filled." And they were in great fear, and in truth they believed in Christ, and said, "This is the King Who hath come down from heaven and become man." And Perôzdhâdh answered and said unto them, "Now know I that the prophecy of Isaiah is true. For when I was in the school of the Hebrews I read in [the Book of] Isaiah, and I found [written] therein thus: 'For unto us a child is born, and unto us a son hath been given. And His Name shall be called Wonderful, and Counsellor, and God, Giant of the Worlds'" (Isa. ix. 6). And it is written in another place, "Behold, a virgin is with child, and she shall bring forth a son, and his name shall be called 'Emmanuel,' which is, being interpreted, 'God with us'" (Isa. vii. 14). And because He became like a man, and the angels were coming down from heaven to Him, truly He is the Lord of angels and men. And all the Magi believed and said, "Truly this King is God. Kings are born unto us frequently, and mighty men, the sons of mighty men, are born unto us on earth, but it is an unheard-of thing for the angels to come down to them." And straightway they all rose up, and did homage to Him as the Lord and King of the world. And having prepared food for their journey, they went down to their own country by a desert road.