The tithe was a requirement of the law in which all Israelites
were give 10% of everything they earned and grew to the Tabernacle
/ Temple (Leviticus 27:30; Numbers 18:26; Deuteronomy 14:24; 2
Chronicles 31:5).
Now that we are under the
new covenant, we are not bound by the law. Luke 22:20 says,
"After supper, [Jesus] took another cup of wine and said, 'This
wine is the token of God's new covenant to save you an agreement
sealed with the blood I will pour out for you.'"
So I believe tithing is not compulsary and Christians should not
feel obligated to always tithe. But we can use the 10% and 20%
thingy as a guide
to how much we want to give back to God. We should give as we are
able, in keeping with our income.
Each man should give what he has decided in his heart to give,
not reluctantly or under
compulsion, for God loves a cheerful giver (2 Corinthians
9:7).
Regards