To "tithe" means "to give or take the tenth of." In Scripture it refers to giving a tenth of "all the increase" (Deuteronomy 14:22) derived from one's produce, property or income for the support of a religious purpose. The motivation to tithe is a worshipful recognition of God as the Creator and Possessor of the entire universe and everything in it, including ourselves.
Although tithing became a codified, or written, law under the covenant God made with ancient Israel at Mount Sinai, it was historically practiced among those who were faithful to God before that covenant. Abraham, after defeating a coalition of kings who had kidnapped his nephew, tithed on the spoils of the war to Melchizedek, priest of God Most High (Genesis 14:18-22).
Abraham obviously understood giving a tenth as the appropriate way to honor God with one's physical possessions. It is also noteworthy that Abraham gave the tenth to Melchizedek, a representative of the Creator God. (In fact, this same Melchizedek was the divine Word who was later born in the flesh as Jesus Christ, as is shown in Hebrews 7:1-3.)
Abraham recognized the underlying premise for giving a tithe to God: He is the actual "Possessor of heaven and earth" who made his victory and all blessings possible.
God reminds us throughout the Bible, and people of God respectfully acknowledge, that everything belongs to God (Exodus 19:5; Job 41:11; Psalm 24:1; 50:12; Haggai 2:8). "And you shall remember the Lord your God," Moses told Israel, "for it is He who gives you power to get wealth" (Deuteronomy 8:18). Tithing is thus, first and foremost, an act of worshipful recognition of God as our source of existence, blessing and providence.
Jacob also followed the example of his grandfather Abraham. When God reconfirmed to him the promises He had made to Abraham, Jacob promised God, "Of all that You give me I will surely give a tenth [or tithe] to You" (Genesis 28:20-22).
The practice of tithing was later incorporated into the covenant with Israel as a written law. The tribe of Levi, devoted to the nation's religious service and not given an inheritance of land from which to derive increase (Numbers 18:23), was to receive the tithe of Israel's agricultural produce in return for its service. The Levites, based on what they had received in tithes from the people, in turn tithed to the priestly family of Aaron (verses 26-28).
As time passed, the tithe was carelessly neglected. Following the Jewish return from Babylonian exile, God corrected the nation over this matter in the strongest of terms (Malachi 3:8-10). Failure to tithe, God said, was tantamount to robbing Him, and the people were consequently cursed. Yet He also promised that renewed obedience in tithing would result in blessings from Him so abundant that "there [would] not be room enough to receive it."
Actually, God said here that the people robbed him in "tithes and offerings"—showing that they were expected to give additional offerings beyond their tithe, the amounts of which were personally determined. Offerings could be given at any time but were specifically required during God's festival seasons, when each was to give as he was able, in accordance with the blessings he had received from God (Deuteronomy 16:16-17).
Several centuries later, Jesus Himself clearly upheld the practice of tithing, stating: "Woe to you, scribes and Pharisees, hypocrites! For you pay tithe of mint and anise and cummin [garden herbs], and have neglected the weightier matters of the law: justice and mercy and faith. These you ought to have done, without leaving the others undone" (Matthew 23:23).
Rather than abolishing the practice of tithing, Christ plainly confirmed His will that tithing should indeed be practiced in even seemingly minor aspects of one's increase, along with sincere adherence to other "weightier [or more important] matters" they were obviously neglecting.
As tithes and offerings in Israel were given to the tribe of Levi for their livelihood and service to God, the Church in the first century provided financial support for Christ's ministers to carry out their work. Instances of and principles relating to this practice are found in several passages (see Luke 10:1, 7-8; 1 Corinthians 9:7-14; 2 Corinthians 11:7-9; Philippians 4:14-18; Hebrews 7).
In Deuteronomy 14 we see the practice of tithing required for two other purposes—having the means to attend and celebrate God's festivals (verses 22-27) and caring for the poor and needy (verses 28-29). Since we believe in observing God's festivals (listed in Leviticus 23) and we believe in taking care of the poor and needy, we acknowledge the continuity of the tithing described for these purposes.
The United Church of God teaches that tithing remains a universal law and that one's willing obedience to this law reflects the unselfish, giving nature of our Creator and Provider (2 Corinthians 9:6-8).
Concerning administration of this law, it is the duty of the Church to teach people to tithe, but it is the responsibility of the individual to obey. Tithing is a personal matter of faith between the individual and his Creator.
We teach that anyone devoted to following God should obey Him in this fundamental way, but it is not appointed to the Church to enforce and regulate tithe-paying. Because of the economic complexities in today's societies, the Church regularly receives many technical questions about tithing, and we seek to provide wise administrative guidelines according to God's will and direction.
Regarding voluntary giving beyond the tithing that God requires, He desires that we be generous with the blessings He's given us—willing to help others through contributing to the work of His Church in proclaiming His truth and caring for the needs of members. And we are to help the needy we encounter as we are able. Scripture shows that while we must properly provide for our families and be wise stewards of our resources, we are also to be giving and caring people.
Through tithing and additional voluntary offerings that spring from willing and cheerful giving (2 Corinthians 9:6-8), we both honor God and support the physical means for doing His work of proclaiming the gospel to the world and making disciples among all the nations (Matthew 24:14; 28:19-20). God has provided the perfect financial system, which takes care of the needs of His work, the personal need to attend His festivals and the need to care for the poor.
For more details, read What Does the Bible Teach About Tithing?