The Hebrews verses,in addition to pointing to Melchizidek's greatness, refer to “the Law” requiring the collecting of tithes by “the Levites”. In Christianity, we aren’t under the law and we do not have Levites.
"For he himself is our peace, who has made the two one and has destroyed the barrier, the dividing wall of hostility, by abolishing in his flesh the law with its commandments and regulations." (Ephesians 2:14,15)
Some point to Jesus’ reprimand of the Pharisees’ hypocrisy as justification for Christian tithing but overlook the fact that He was speaking to Jewish Pharisees, not to Christians (again, who are not under the Law). If we were to be like the Pharisees, we would be following the law (613 parts) to it’s “nth” degree along with all their add-ons, we would be sacrificing animals for our sins and we wouldn’t eat with Gentiles (oops, that’s me)!
"Woe to you, teachers of the law and Pharisees, you hypocrites! You give a tenth of your spices--mint, dill and cumin. But you have neglected the more important matters of the law--justice, mercy and faithfulness. You should have practiced the latter, without neglecting the former. You blind guides! You strain out a gnat but swallow a camel.” (Matthew 23:23,24)
The favorite scripture quoted by those who teach tithing to the local church is Malachi 3:8-11: “You are under a curse—the whole nation of you—because you are robbing me. Bring the whole tithe into the storehouse that there may be food in my house.” This is the context for Malachi 3:8:
“I will be quick to testify against sorcerers, adulterers and perjurers, against those who defraud laborers of their wages, who oppress the widows and the fatherless, and deprive aliens of justice, but do not fear me," says the LORD Almighty.” (Malachi 3:2-7)
This is a reference to God’s requirement for Israel to obey the Law that they were to bring food: wine, grain, olive oil, meat--not money, (this was separate from their monetary system) into the storehouse of the Tabernacle or Temple, (which the church is not; a woman who “was raised in a Jewish home” pointed out that the tithing teaching is a type of "replacement theology",designating the church building as a replacement for the Temple). Every first and second year they were to take this food to the designated place and eat it themselves in the presence of the Lord but still remembering to include the Levites.
"You must not worship the LORD your God in their way. But you are to seek the place the LORD your God will choose from among all your tribes to put his Name there for his dwelling. To that place you must go; there bring your burnt offerings and sacrifices, your tithes and special gifts, what you have vowed to give and your freewill offerings, and the firstborn of your herds and flocks. There, in the presence of the LORD your God, you and your families shall eat and shall rejoice in everything you have put your hand to, because the LORD your God has blessed you." (Deuteronomy 12:5-7)
The Levites were to give a tithe from what they got in the third year to Aaron or the chief priest.
"Say to the Levites: “When you present the best part, it will be reckoned to you as the product of the threshing floor or the winepress. You and your households may eat the rest of it anywhere, for it is your wages for your work at the Tent of Meeting. By presenting the best part of it you will not be guilty in this matter; then you will not defile the holy offerings of the Israelites, and you will not die." (Numbers 18:30-32)
In the third year, the Israelites were to give that tenth of food to the Levites, aliens, orphans, and widows, so it was a four-way split. The Israelites in Malachi’s time were robbing God by not taking care of the aliens (read immigrants), widows and orphans and apparently the Levites weren’t sharing what they did get!
"When you have finished setting aside a tenth of all your produce in the third year, the year of the tithe, you shall give it to the Levite, the alien, the fatherless and the widow, so that they may eat in your towns and be satisfied. Then say to the LORD your God: "I have removed from my house the sacred portion and have given it to the Levite, the alien, the fatherless and the widow, according to all you commanded. I have not turned aside from your commands nor have I forgotten any of them." (Deuteromony. 26:12-13)
There is no New Covenant equivalent of the Aaronic Priesthood or the Levites; the Temple sacrificial system is over.
If perfection could have been attained through the Levitical priesthood (for on the basis of it the law was given to the people), why was there still need for another priest to come--one in the order of Melchizedek, not in the order of Aaron? For when there is a change of the priesthood, there must also be a change of the law. (Hebrews 7:11-12)
Day after day every priest stands and performs his religious duties; again and again he offers the same sacrifices, which can never take away sins. But when this priest had offered for all time one sacrifice for sins, he sat down at the right hand of God. Since that time he waits for his enemies to be made his footstool, because by one sacrifice he has made perfect forever those who are being made holy. (Hebrews 10:11-14)
So, if we were to remain under the Law, (the very thought of such horrified Paul as he wrote to the Galatians) we would be tithing from our fields and flocks, not our money. We would eat that tithe ourselves at the central location, which God designated for all Christians to gather for worship in the first and second years (could be a very long trek!). In the third year we would divide that tithe of food between the pastors, immigrants, orphans and widows. However,Scripture says that if one aims to be justified by following any part of the law, one must keep the entire Law and be judged by it or be under a curse! SCAREY!
All who rely on observing the law are under a curse, for it is written: "Cursed is everyone who does not continue to do everything written in the Book of the Law." Clearly no one is justified before God by the law, because, "The righteous will live by faith." The law is not based on faith; on the contrary, "The man who does these things will live by them." Christ redeemed us from the curse of the law by becoming a curse for us, for it is written: "Cursed is everyone who is hung on a tree." He redeemed us in order that the blessing given to Abraham might come to the Gentiles through Christ Jesus, so that by faith we might receive the promise of the Spirit. (Galatians 3:10-14)
But, the prosperity teachers say, when you give ten percent to us (I’m still amazed that this erroneous teaching prevails twenty years after it’s been thoroughly debunked by many Bible teachers), God will multiply it and “rebuke the devourer”. We’ve heard, “tithe and your appliances and cars won’t break down”. We tithed but our appliances and cars broke down. In fact we were hurting financially but the church got theirs. Occasionally this works for some people but you don’t hear the prosperity teachers talking about the cases where it didn’t work—this is correlation, not causation (two unrelated events happening at the same time without one causing the other). I can only conclude that when people are under compulsion to do a certain thing that the Bible doesn’t teach ("traditions of men"), under many pains of shame, accusations of sin and supposed curse if they don’t—that if somehow it does “work” it’s more likely magic than miracle. Noah Webster (Webster’s 1828 Dictionary, the Webster’s) says “the doing of things not required by God (as a religious rite)” is superstition. I shudder to think about it.
And it’s not just the prosperity teachers who proclaim tithing, most evangelical preachers teach it, but without the pay-off. All you get from their version is a “spiritual blessing” which doesn’t really have a basis in scripture either, certainly not in the “Malachi 3” one. You can be assured that on payday they will want their paychecks, they won’t be satisfied with a spiritual blessing alone.