The answer comes from the biblical definition of “tithe” as only holy food from inside God’s only Old Covenant land of Israel which God had increased. Tithes could not come from what man produced, from Gentiles or from outside of Israel. Period.
In order for somebody to biblically give holy tithes today:
1. They must be a Hebrew living under the Old Covenant (Ex 19:5-6).
2. They must be a Hebrew living inside a holy land of Israel (Lev 27:30-33).
3. They must be a Hebrew and only tithe food miraculously increased inside a holy Israel (Lev 27:30-33).
4. They must give Levitical tithes of food to a holy Levitical servant-hood (Num 18:21-24; Neh 10:37b) who tithes to a holy Aaronic priesthood (Num 18:25-28; Neh 10:38).
5. They must not deliberately share their Old Covenant with Gentiles (Ex 23:32; Deu 7:2).
6. They must not use tithes to support the proselytizing of Gentiles Ex 23:32; Deu 7:2).
7. They must give tithes to Levites who have forfeited their right to own property (Num 18:21-28).
Christians may call giving 10% of their income “tithing” but it not does not meet the biblical definition or purpose of tithing. They are merely giving freewill offerings of 10% and calling such “tithing.”