"If the Mosaic Law required one tenth of one's belongings, then how much more should the Supreme Law of Christ himself require? Of course, that does not mean that Jehovah's Witnesses are required to donate a certain amount, let's say 20%, but rather, that they feel impelled by their conscience and by Christ's death to do so."
[Possible content of a future BOE letter. Soon, in a Kingdom Hall near you.]