Tithing & Circumcision Are NOT Christians
In keeping things simple here. Circumcision is a Jewish thing, but not a Christian thing. Even so is tithing a Jewish thing but not a Christian thing. And what I mean by these statements is they are both a part of the law of Moses in the Old Testament. They are not commanded of us after the Lord Jesus Christ died for our sins, was buried, and rose again. All parts of the law for righteousness, including both circumcision and paying tithe has been done away with in Christ Jesus at the cross. Just read some simple scripture for this matter and allow the word of God to be what teaches us, not any vain tradition.
CIRCUMCISION:
Acts 15:1 & 10-11 KJV And certain men which came down from Judaea taught the brethren, and said, Except ye be circumcised after the manner of Moses, ye cannot be saved. (10) Now therefore why tempt ye God, to put a yoke upon the neck of the disciples, which neither our fathers nor we were able to bear? (11) But we believe that through the grace of the Lord Jesus Christ we shall be saved, even as they.
Galatians 5:2-4 KJV Behold, I Paul say unto you, that if ye be circumcised, Christ shall profit you nothing. (3) For I testify again to every man that is circumcised, that he is a debtor to do the whole law. (4) Christ is become of no effect unto you, whosoever of you are justified by the law; ye are fallen from grace.
TITHING:
Hebrews 7:5 KJV And verily they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham:
Romans 10:3-4 KJV For they being ignorant of God's righteousness, and going about to establish their own righteousness, have not submitted themselves unto the righteousness of God. (4) For Christ is the end of the law for righteousness to every one that believeth.
It really is a headscratcher that someone would willfully want to go back under a yoke of bondage (Galatians 5:1). Such a yoke being the law once we are made free from it. Furthermore when it was told this bondage was done away with, the people received the news of the gospel with joy (Acts 13:48).
To sum up circumcision and tithing, they are clearly apart of the law, not part of the grace of God. If something is by the law of Moses then it is of works for righteousness. If it is of works it can not possibly be of grace according to scripture.
Romans 11:6 KJV And if by grace, then is it no more of works: otherwise grace is no more grace. But if it be of works, then is it no more grace: otherwise work is no more work.
Romans 3:27-28 KJV Where is boasting then? It is excluded. By what law? of works? Nay: but by the law of faith. (28) Therefore we conclude that a man is justified by faith without the deeds of the law.
Ephesians 2:8-9 KJV For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: (9) Not of works, lest any man should boast.
So don't let any man tell you otherwise. If there is such an one saying you should still circumcise or pay tithe just know that they are a deceiver; anyone to say such a thing has not accepted the salvation in Christ, but thinks they play a part in the gift of God in salvation.
Galatians 2:21 KJV I do not frustrate the grace of God: for if righteousness come by the law, then Christ is dead in vain.
Colossians 2:8-10 & 18- 19 KJV Beware lest any man spoil you through philosophy and vain deceit, after the tradition of men, after the rudiments of the world, and not after Christ. (9) For in him dwelleth all the fulness of the Godhead bodily. (10) And ye are complete in him, which is the head of all principality and power: (18) Let no man beguile you of your reward in a voluntary humility and worshipping of angels, intruding into those things which he hath not seen, vainly puffed up by his fleshly mind, (19) And not holding the Head, from which all the body by joints and bands having nourishment ministered, and knit together, increaseth with the increase of God.
Here are a few Video-Bible-Studies on both these topics covering many other points in the word of God to the same simple answer laid out above.