If you read the New Testament you will see that circumcision is irrelevant. It was required under the Mosaic law, but Christians are not under the Mosaic law but under grace. Paul wrote to the church in Corinth, "This is the rule I lay down in all the churches. Was a man already circumcised when he was called? He should not become uncircumcised. Was a man uncircumcised when he was called? He should not be circumcised. Circumcision is nothing and uncircumcision is nothing."
I have read the NT and I have not found circumcision irrelevant and the same arguments could be used to support the keeping circumcision as are used regarding the keeping of the Law and the Sabbath; I have to admit that I have encountered anyone advocating circumcision in this sense.
Circumcision was a prequisite to the covenant, one could not be included in the covenant without circumcision; one could not be counted in the twelve tribes if not circumcised. If we consider the Law to be the first four books of the “Law and the Prophets”, then circumcision is a part of what cannot be changed.
Luke 16:16-17 (RSV)
16 "The law and the prophets were until John; since then the good news of the kingdom of God is preached, and every one enters it violently.
17 But it is easier for heaven and earth to pass away, than for one dot of the law to become void.
Just because the the Kingdom is preached more so than the Law, does not mean the Law is irrelevant, be cause Jesus preached also the Law.
Matthew 7:23 (NKJV)
23 And then I will declare to them, 'I never knew you; depart from Me, you who practice lawlessness!'
Matthew 13:41 (NKJV)
41 The Son of Man will send out His angels, and they will gather out of His kingdom all things that offend, and those who practice lawlessness,
Matthew 23:31 (NKJV)
31 Therefore you are witnesses against yourselves that you are sons of those who murdered the prophets.
Isaiah 33:14-15 (NKJV)
14 The sinners in Zion are afraid; Fearfulness has seized the hypocrites: "Who among us shall dwell with the devouring fire? Who among us shall dwell with everlasting burnings?"
15 He who walks righteously and speaks uprightly, He who despises the gain of oppressions, Who gestures with his hands, refusing bribes, Who stops his ears from hearing of bloodshed, And shuts his eyes from seeing evil:
Isaiah 28:16-18 (NKJV)
16 Therefore thus says the Lord GOD: "Behold, I lay in Zion a stone for a foundation, A tried stone, a precious cornerstone, a sure foundation; Whoever believes will not act hastily.
17 Also I will make justice the measuring line, And righteousness the plummet; The hail will sweep away the refuge of lies, And the waters will overflow the hiding place.
18 Your covenant with death will be annulled, And your agreement with Sheol will not stand; When the overflowing scourge passes through, Then you will be trampled down by it.
These kind of studies studies make me feel uneasy. The return of Christ could be as close as seven years which would mean a lot worse than covid 19 is ahead in our time.
1 Corinthians 7:18-20 (NKJV)
18 Was anyone called while circumcised? Let him not become uncircumcised. Was anyone called while uncircumcised? Let him not be circumcised.
19 Circumcision is nothing and uncircumcision is nothing, but keeping the commandments of God
is what matters.
20 Let each one remain in the same calling in which he was called.
We should note that Jesus could not change the Law. The Law is the rock foundation, if the Law could be changed it would not be rock, the Law would be sand. If the Law could be changed Christ would have no credentials or identity, that would distinguish Him from the evil one who has presumed to have changed the Law.
Had Paul been introduced by way of prophesy; for example:
Luke 16:16-17 (RSV)
16 "The law and the prophets were until John; since then the good news of the kingdom of God is preached, and every one enters it violently.
17 But it is easier for heaven and earth to pass away, than for one dot of the law to become void;
UNLESS ONE GREATER THAN I DID IT, CALLED PAUL.
I do not judge Paul the person; he is not my business; I could say I never knew him; but as the Lord liveth, for whatever reason, the epistle stinks.