Commentaries:
The third tithe is an additional tithe, entirely separate from the first tithe that supports God's work of preaching the gospel and the second tithe that enables church members to attend the feasts. Like first tithe, second tithe is paid yearly. Just as the law of canceling debts is based on a cycle of seven years, the third tithe is paid only on the increase earned during the third and sixth years of a seven-year cycle. Since Christians are not spiritual Israelites (Galatians 3:29; 6:16) until converted and baptized, they do not save this third tithe until the third year after their baptism. Most members of the church count their third-tithe years from either the Passover or the Feast of Tabernacles closer to the date of their baptism.
Martin G. Collins
Tithing: Third Tithe