Where did the guideline of giving ten percent begin in the Bible?
The guideline of giving ten percent began with Abraham in Genesis 14, when he gave a tenth of the spoils to Melchizedek after defeating the kings who had overrun Sodom and recovering Lot. It is presented as a guideline, not a mandatory law.
Les explains that the guideline of giving ten percent began way back with Abraham in Genesis chapter 14. After Abraham defeated the kings that had overrun Sodom and brought Lot back, he gave ten percent of the spoil to Melchizedek. Les says this is a guideline, but he insists that mandating ten percent puts people back under the law—and Paul never says that. Instead, Paul says to give as the Lord has prospered you; you are not under a mandate of law but are left to your own free conscience, led by the Holy Spirit, to give as God has prospered you.
And it came to pass in the days of Amraphel king of Shinar, Arioch king of Ellasar, Chedorlaomer king of Elam, and Tidal king of nations;