The amount of tithe comes directly from the Old Testament and it has to do wth giving to god what is his. Of course the chirstian church in its early days had instructed its members to give much more than 10%… People were required to have things in common and so they sold their houses and land and possessions and laid the money at the apostles feet to be distributed accordingly. Those who lied about their possessions had their life taken from them by god. (See acts 4: 32-37; acts 5: 1-11)
Considering those times, 10% is nothing in comparison.
The mormon have something comparable to those times called the United Order. This is an interesting concept. JS tried to do it in the early days but the lds were not ready for such a sacrafice. And they still aren’t. And so, no United Order yet.
GUIDE TO THE SCRIPTURES
United Order
See also Consecrate, Law of Consecration
An organization through which the Saints in the early days of the restored Church sought to live the law of consecration. Individuals shared property, goods, and profits, receiving these things according to their wants and needs (D&C 51: 3; 78: 1-15; 104).
In your temporal things you shall be equal, D&C 70: 14. The Saints were to be organized to be equal in all things, D&C 78: 3-11 (D&C 82: 17-20). The Lord gave unto the united order a revelation and a commandment, D&C 92: 1. John Johnson should become a member of the united order, D&C 96: 6-9. The Lord gave general instructions for operating the united order, D&C 104. My people are not united according to the union required by the celestial kingdom, D&C 105: 1-13.
scriptures.lds.org/en/gs/u/6