Gospel Doctrine, p. 228 “The bishop should encourage every man, woman and child who earns and receives a return for labor, to honor the 
2 Corinthians 9:6-7 “But this I say, He which soweth sparingly shall reap also sparingly; and he which soweth bountifully shall reap also bountifully. 7 Every man according as he purposeth in his heart, so let him give; not grudgingly, or of necessity: for God loveth a cheerful giver.” [emp. added]
Gospel Doctrine is pretty much an encyclopedic work of Joseph F. Smith’s sermons. As an FYI, he was Joseph Smith’s nephew. His works are used extensively in LDS teachings, and you can find many LDS leaders who frequently quote him in their own sermons/talks.
As the Apostle Paul said, people should give whatever the Lord laid on their heart. Tithing is between the giver, and the Lord, and it certainly can’t buy our way into heaven! This type of doctrine is what Joseph Smith railed against in his day. Hence, Mormonism is in existence today. One only needs to remember what Joe wrote in Mormon 8:32 ——
“Yea, it shall come in a day when there shall be churches built up that shall say: Come unto me, and for your money you shall be forgiven of your sins.”
Although Mr. Smith delivered this sermon in 1900, the same doctrines still apply. If you don’t pony up, there’s no salvation for you.
We also recommend a great article written by Dave Ramsey. He provided a simple explanation of why it’s important to understand Christians don’t lose salvation if they choose not to tithe, although our lives are blessed abundantly by doing so!
Pray for those in the Church who believe they can buy their way into heaven. Also pray for them to wonder if their tithing amounts to the same worth of Jesus’ spilt blood!
With Love in Christ;
Michelle