Attempt to use Galatians to argue that the law has been abolished and I will use Galatians to refute your attempt .
Either the law ended, OR, follow the law.
THE FIRST TITHE
Leviticus 27:30-33 defines this tithe as a tenth of crops and animals in herds and flocks.
Numbers 18 gives the ordinances, or instructions, for this tithe, and commands this tithe be taken to the Levites.
Purpose of this tithe: to support the Levitical Priesthood.
SECOND TITHE
Deuteronomy 14:22-27: aka The Festival Tithe - a tenth of crops, plus add to that the firstborn animals, and take to the yearly feasts.
Purpose of this tithe: that thou mayest learn to fear the LORD thy God always
THIRD TITHE
Deuteronomy 14:28-29: aka The Three-Year Tithe aka The Poor Tithe - a tenth of crops, kept at home, and invite the Levites, widows, orphans, stranger to eat.
Purpose of this tithe: to feed the poor.
The ONLY people in the Old Testament that were commanded to tithe were those who INHERITED THE PROMISED LAND WITH EVERYTHING ON IT. They got the land, house, animals, crops, etc. ALL FREE AND CLEAR. No mortgage payment or rent to pay. And THEY were commanded to tithe on the crops and animals and take it to the Levites who INHERITED the tithe INSTEAD OF the promised land with everything on it. No one else tithed. Wage earners did not tithe. Jesus did not tithe as a carpenter. Paul did not tithe as a tent maker. Peter did not tithe as a fisherman.
You won't find ANY command to tithe money. You won't find ANY command to tithe from your income. You won't find ANY command to take the tithe to the local church organization.
But, does the scripture tell us we are not under the law?
Matthew 5:17-18 states Christ came to fulfill the law and not abolish it.
This is where some education in law is useful. What does fulfill mean? What does abolish mean?
Let me give an example. A legal contract is enforceable under the law. Lets say you hire a contractor to build a swimming pool in your back yard. Once the contractor has completed the job, and everything in that contract has been completed, the contract has been fulfilled. The contractors job is to fulfill the contract, not abolish it. He fulfills it by completing the terms, bringing it to an end.
Consider:
Hebrews 8:13 (KJV) - In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
Colossians 2:14 (KJV) - Blotting out the handwriting of ordinances that was against us, which was contrary to us, and took it out of the way, nailing it to his cross;
Galatians 5:18 (KJV) - But if ye be led of the Spirit, ye are not under the law.
Galatians 3:19 (KJV) - Wherefore then serveth the law? It was added because of transgressions, till the seed should come to whom the promise was made; and it was ordained by angels in the hand of a mediator.
Until the Seed to whom the promise referred had come. In other words, until Jesus came and fulfilled the law.
Galatians 3:23-25 (KJV)
23But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed.
24Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith.
25But after that faith is come, we are no longer under a schoolmaster.
Galatians 3:10-14 (KJV)
10For as many as are of the works of the law are under the curse: for it is written, Cursed is every one that continueth not in all things which are written in the book of the law to do them.
11But that no man is justified by the law in the sight of God, it is evident: for, The just shall live by faith.
12And the law is not of faith: but, The man that doeth them shall live in them.
13Christ hath redeemed us from the curse of the law, being made a curse for us: for it is written, Cursed is every one that hangeth on a tree:
14That the blessing of Abraham might come on the Gentiles through Jesus Christ; that we might receive the promise of the Spirit through faith.
So, either accept that the law ended, OR comply with the law.
It really doesn't matter to me as far as tithing goes. If we are under the law, the tithing laws didn't apply to wage earners or to anyone's income.