The Test and Promise of Tithing

"God requires one-tenth of our increase to be put into His storehouse; and this is given as a standing law to all of the Stakes of Zion.  By this principle (tithing) the loyalty of the people of this Church shall be put to the test. By this principle it shall be known who is for the kingdom of God and who is against it. By this principle it shall be seen whose hearts are set on doing the will of God and keeping his commandments, thereby sanctifying the land of Zion unto God, and who are opposed to this principle and have cut themselves off from the blessings of Zion. There is a great deal of importance connected with this principle, for by it it shall be known whether we are faithful or unfaithful. In this respect it is as essential as faith in God, as repentance of sin, as baptism for the remission of sin, or as the laying on of hands for the gift of the Holy Ghost.

The law of tithing is a test by which the people as individuals shall be proved. Any man who fails to observe this principle shall be known as a man who is indifferent to the welfare of Zion, who neglects his duty as a member of the Church, and who does nothing toward the accomplishment of the temporal advancement of the kingdom of God. He contributes nothing, either, toward spreading the gospel to the nations of the earth, and he neglects to do that which would entitle him to receive the blessings and ordinances of the gospel. . . 

I have said, and I will repeat it here, that a man or woman who will always pay his or her tithing will never apostatize. It does not make any difference how small or how large it may be; it is a law of the Lord; it is a source of revenue for the Church; it is God’s requirement, and He has said that those who will not observe it are not worthy of an inheritance in Zion. No man will ever apostatize so long as he will pay his tithing. It is reasonable. Why? Because as long as he has faith to pay his tithing he has faith in the Church and in the principles of the Gospel, and there is some good in him, and there is some light in him. As long as he will do this the tempter will not overcome him and will not lead him astray."

-- TPC: Joseph F. Smith, chapter 31.

Malachi 3: 8-10 Will a man rob God? Yet ye have robbed me. But ye say, Wherein have we robbed thee? In tithes and offerings. Ye are cursed with a curse: for ye have robbed me, even this whole nation.  Bring ye all the tithes into the storehouse, that there may be meat in mine house, and prove me now herewith, saith the Lord of hosts, if I will not open you the windows of heaven, and pour you out a blessing, that there shall not be room enough to receive it.

Matt 6:24 No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.

Doctrine and Covenants 82:10 I, the Lord, am bound when ye do what I say; but when ye do not what I say, ye have no promise.

Doctrine and Covenants 82:20-21 There is a law, irrevocably decreed in heaven before the foundations of this world, upon which all blessings are predicated—And when we obtain any blessing from God, it is by obedience to that law upon which it is predicated.