so, aside from the harshness here, it would actually be beneficial to take a look at verses within the law talking about tithing.
There seem to be five chapters (Leviticus 27, Numbers 18, Deuteronomy 12, 14, 26) that talk about tithing as a law. I'm just going to list them and then make some general comments on the passages.
Leviticus 27:30-34
30 And all the tithe of the land, whether of the seed of the land or of the fruit of the tree, is the Lord’s. It is holy to the Lord. 31 If a man wants at all to redeem any of his tithes, he shall add one-fifth to it. 32 And concerning the tithe of the herd or the flock, of whatever passes under the rod, the tenth one shall be holy to the Lord. 33 He shall not inquire whether it is good or bad, nor shall he exchange it; and if he exchanges it at all, then both it and the one exchanged for it shall be holy; it shall not be redeemed.’” 34 These are the commandments which the Lord commanded Moses for the children of Israel on Mount Sinai.
Numbers 18:21-32
21 “Behold, I have given the children of Levi all the tithes in Israel as an inheritance in return for the work which they perform, the work of the tabernacle of meeting. 22 Hereafter the children of Israel shall not come near the tabernacle of meeting, lest they bear sin and die. 23 But the Levites shall perform the work of the tabernacle of meeting, and they shall bear their iniquity; it shall be a statute forever, throughout your generations, that among the children of Israel they shall have no inheritance. 24 For the tithes of the children of Israel, which they offer up as a heave offering to the Lord, I have given to the Levites as an inheritance; therefore I have said to them, ‘Among the children of Israel they shall have no inheritance.’” 25 Then the Lord spoke to Moses, saying, 26 “Speak thus to the Levites, and say to them: ‘When you take from the children of Israel the tithes which I have given you from them as your inheritance, then you shall offer up a heave offering of it to the Lord, a tenth of the tithe. 27 And your heave offering shall be reckoned to you as though it were the grain of the threshing floor and as the fullness of the winepress. 28 Thus you shall also offer a heave offering to the Lord from all your tithes which you receive from the children of Israel, and you shall give the Lord’s heave offering from it to Aaron the priest. 29 Of all your gifts you shall offer up every heave offering due to the Lord, from all the best of them, the consecrated part of them.’ 30 Therefore you shall say to them: ‘When you have lifted up the best of it, then the rest shall be accounted to the Levites as the produce of the threshing floor and as the produce of the winepress. 31 You may eat it in any place, you and your households, for it is your reward for your work in the tabernacle of meeting. 32 And you shall bear no sin because of it, when you have lifted up the best of it. But you shall not profane the holy gifts of the children of Israel, lest you die.’”
Deuteronomy 12:5-14
5 “But you shall seek the place where the Lord your God chooses, out of all your tribes, to put His name for His dwelling place; and there you shall go. 6 There you shall take your burnt offerings, your sacrifices, your tithes, the heave offerings of your hand, your vowed offerings, your freewill offerings, and the firstborn of your herds and flocks. 7 And there you shall eat before the Lord your God, and you shall rejoice in all to which you have put your hand, you and your households, in which the Lord your God has blessed you.
8 “You shall not at all do as we are doing here today—every man doing whatever is right in his own eyes— 9 for as yet you have not come to the rest and the inheritance which the Lord your God is giving you. 10 But when you cross over the Jordan and dwell in the land which the Lord your God is giving you to inherit, and He gives you rest from all your enemies round about, so that you dwell in safety, 11 then there will be the place where the Lord your God chooses to make His name abide. There you shall bring all that I command you: your burnt offerings, your sacrifices, your tithes, the heave offerings of your hand, and all your choice offerings which you vow to the Lord. 12 And you shall rejoice before the Lord your God, you and your sons and your daughters, your male and female servants, and the Levite who is within your gates, since he has no portion nor inheritance with you. 13 Take heed to yourself that you do not offer your burnt offerings in every place that you see; 14 but in the place which the Lord chooses, in one of your tribes, there you shall offer your burnt offerings, and there you shall do all that I command you.
Deuteronomy 14:22-29
22 “You shall truly tithe all the increase of your grain that the field produces year by year. 23 And you shall eat before the Lord your God, in the place where He chooses to make His name abide, the tithe of your grain and your new wine and your oil, of the firstborn of your herds and your flocks, that you may learn to fear the Lord your God always. 24 But if the journey is too long for you, so that you are not able to carry the tithe, or if the place where the Lord your God chooses to put His name is too far from you, when the Lord your God has blessed you, 25 then you shall exchange it for money, take the money in your hand, and go to the place which the Lord your God chooses. 26 And you shall spend that money for whatever your heart desires: for oxen or sheep, for wine or similar drink, for whatever your heart desires; you shall eat there before the Lord your God, and you shall rejoice, you and your household. 27 You shall not forsake the Levite who is within your gates, for he has no part nor inheritance with you.
28 “At the end of every third year you shall bring out the tithe of your produce of that year and store it up within your gates. 29 And the Levite, because he has no portion nor inheritance with you, and the stranger and the fatherless and the widow who are within your gates, may come and eat and be satisfied, that the Lord your God may bless you in all the work of your hand which you do.
Deuteronomy 26: 1-15
“And it shall be, when you come into the land which the Lord your God is giving you as an inheritance, and you possess it and dwell in it, 2 that you shall take some of the first of all the produce of the ground, which you shall bring from your land that the Lord your God is giving you, and put it in a basket and go to the place where the Lord your God chooses to make His name abide. 3 And you shall go to the one who is priest in those days, and say to him, ‘I declare today to the Lord your[
a] God that I have come to the country which the Lord swore to our fathers to give us.’
4 “Then the priest shall take the basket out of your hand and set it down before the altar of the Lord your God. 5 And you shall answer and say before the Lord your God: ‘My father was a Syrian,[
b] about to perish, and he went down to Egypt and dwelt there, few in number; and there he became a nation, great, mighty, and populous. 6 But the Egyptians mistreated us, afflicted us, and laid hard bondage on us. 7 Then we cried out to the Lord God of our fathers, and the Lord heard our voice and looked on our affliction and our labor and our oppression. 8 So the Lord brought us out of Egypt with a mighty hand and with an outstretched arm, with great terror and with signs and wonders. 9 He has brought us to this place and has given us this land, “a land flowing with milk and honey”;[
c] 10 and now, behold, I have brought the firstfruits of the land which you, O Lord, have given me.’
“Then you shall set it before the Lord your God, and worship before the Lord your God. 11 So you shall rejoice in every good thing which the Lord your God has given to you and your house, you and the Levite and the stranger who is among you.
12 “When you have finished laying aside all the tithe of your increase in the third year—the year of tithing—and have given it to the Levite, the stranger, the fatherless, and the widow, so that they may eat within your gates and be filled, 13 then you shall say before the Lord your God: ‘I have removed the holy tithe from my house, and also have given them to the Levite, the stranger, the fatherless, and the widow, according to all Your commandments which You have commanded me; I have not transgressed Your commandments, nor have I forgotten them. 14 I have not eaten any of it when in mourning, nor have I removed any of it for an unclean use, nor given any of it for the dead. I have obeyed the voice of the Lord my God, and have done according to all that You have commanded me. 15 Look down from Your holy habitation, from heaven, and bless Your people Israel and the land which You have given us, just as You swore to our fathers, “a land flowing with milk and honey.”’[
d]
So, a few comments: First, notice the emphasis on the food aspect of the Tithe, bringing it from the field, from the cattle, or wine press, but then notice in Deut 14 that you can exchange it for money if you live too far away, but then when you come to wherever it is you are to tithe, you buy as much food, and alcohol and drink as you want.
That brings to the next obvious point, the eating of the tithe. Especially in Deuteronomy the focus is on feasting on the tithe. Buying all you want and feasting with joy. Even if you had previously exchanged the tithe for the money, you use that to buy more food.
Then there is the levitical aspect of it where the tithe is used to supply the Priests. Notice in Numbers that it is mostly food because the Priests have no inheritance of land within Israel.
Then there is the third year tithing rule where the tithe is placed at the City gate to feed the poor and disenfranchised.
There is the Temple/Tabernacle focus of the Tithe, it is to be given there, and not offered anywhere else. It is also tied in with other offerings and sacrifices.
Notice the point that the tithe is for the Israelites. In Leviticus it was a law commanded by Moses on Mount Sinai to the children of Israel, and it is commanded along with other laws that apply only to Israel.
So, when talking about the tithe, these passages explain what it means. When using the word tithe, you are referring to this practice, and not something else. When it is talked about elsewhere in the Bible it is referring to this. This point may seem obvious but many times the disparity between the words we use and the meaning we are ascribing to those words is too vast in comparison to how the words are used in Scripture.
If you argue for the tithe to be necessary to the Christian, you are saying this form of the tithe is necessary, as it is stated in Scripture, and not a made up version of it that doesn't have any basis in Scripture.