Tithing is part of Mosaic law; the Old Testament describes three tithes that all Israelites had to pay, including 10 percent of all income, tithes for the yearly feasts and tithes for the poor paid every three years. The 10 percent tithe paid the Levitical priesthood's expenses, and tithes from the feasts could be used for any worthy cause. The rich and the poor paid the same percentage.
The earliest mention of tithing appears in Genesis 14. Abraham ransacked Mesopotamia to rescue Lot and took goods with him when he left. He gave 10 percent of his bounty to the priest Melchizedek, and Melchizedek blessed Abraham.
The New Testament only mentions tithing four times. Jesus chastised the Pharisees for putting more emphasis on tithing than love, mercy, justice or faith. Hebrews 7:12 mentions that when priesthood changes, laws must also change, but does not specify whether changing from the Levites' rule to Jesus' rule makes the law of tithing obsolete.
Several Bible verses state that paying tithing brings blessings to the believer. Proverbs 3:9 commands believers to honor the Lord with their wealth, and Proverbs 11:24 states, "One gives freely, yet grows all the richer." Luke 6:38 tells believers that if they give generously, they receive abundant blessings in return.