It is the duty of Christians to contribute 10% of their gross income to the church, so 'that there may be food' in the house of God.(Malachi 3:10) This was required of the people of Israel to help sustain those who served at the alter of God. Today tithes help provide living expenses for pastors, pay utility bills, etc. Since the concerns of our souls are more important than the concerns of our bodies, no one should complain about a tenth.

When a Christian tithes, they are not tithing to the Levitical order, but to the 'order of Melchizedek' - Jesus Christ 'was designated by God to be high priest' of the eternal priesthood.(Psalms 110:4; Hebrews 5:6,10)

'Melchizedek was king of Salem and priest of God Most High' - 'Melchizedek' means 'king of righteousness, and 'king of Salem' means 'king of peace'. Melchizedek brought 'bread and wine' to Abraham.(Genesis 14:18) And Abraham 'gave [Melchizedek] a tenth of everything.'(Hebrews 7:1-2)