This is specifically concerning the content of Hebrews 7 within the context of the entire letter/book of Hebrews along with contextual support from other books within scripture. This is not to say that Christians should not tithe (give ten percent of their earnings). Not only are we required to do so, but we should to do so cheerfully, along with just simply giving an offering (which is different than giving ten percent). Let us remember that when we give to the LORD we are taking part in enhancing His kingdom and it is part of our thanks to Him for all He has done for us (again, along with the general offering that we may give).
NOW UNTO THE TOPIC AT HAND!
The main issue concerning Hebrews 7:1–10 is whether or not it is a valid scripture to use when explaining that whether or not Christians are required to tithe.
Hebrews 7:1–10 cannot be used to justify if Christians should tithe. The purpose of Hebrews 7 is not to establish if Christians should tithe or not. Rather, the purpose of the scripture is to “…[demonstrate] that Melchizedek’s priesthood is superior to the Levitical priesthood.” The verse that some may use to demonstrate that Hebrews 7:1–10 requires Christians to tithe is verse 8 which says, “In the one case tithes are received by mortal men, but in the other case, by one of whom it is testified that he lives” (Heb 7:8, ESV). The subject referred to as “the one” is Melchizedek. However, some interpret “the one” as Jesus Christ. Thus, they interpret the verse as being “a direct reference to Christians giving their tithes to Jesus Christ” though Jesus is not spoken of until Hebrews 7:11.
One must look at the entire context of scripture prior to giving one verse its own meaning. When one looks at the context of Hebrews, they will be able to clearly understand the meaning of Hebrews 7:8. The author of Hebrews 7 is actually describing the superiority of Jesus Christ to the Mosaic covenant. The author describes this superiority in Hebrews 2 and Hebrews 9. Melchizedek’s superiority over the Levitical priesthood is used to describe Jesus’s superiority over the Levitical priesthood because both priesthoods are of the same kind (superior and lasting forever as mentioned in Psalms 110:4). Melchizedek had no Levitical lineage but yet, he was a high priest. He is likened unto Christ who also did not have any Levitcal lineage yet became High Priest. Hebrews 7:3 puts it this way saying that Melchizedek was “…without descent, having neither beginning of days or end of life; but made like unto the Son of God; abideth a priest continually” (Heb 7:3, KJV).
Furthermore, Genesis 14:18–20 demonstrates the example of Abraham giving tithes to Melchizedek. Some may claim that Abraham represents Christians while Melchizedek represents Christ and therefore Hebrews 7 requires Christians to tithe to Christ. However, Abraham giving tithes to Melchizedek was a voluntary sign of thanks and occurred prior to the Mosaic Covenant and that specific institution of tithing. Hebrews 7 is not about tithing but the superiority of Melchizedek’s priesthood to the Levitical priesthood while the entirety of Hebrews emphasizes Christ’s superiority to the law. One writer says “There is still priesthood, but the priesthood of Christ is altogether better: since the order of Melchizedek is an eternal order of priest, it is a better priesthood than that of the Levites.”
 David A. Croteau, Urban Legends of the New Testament (Nashville Tennessee: B&H Publishing Group, 2015, 202
 Ibid., 201.
 Barry C. Joslin, Hebrews, Christ and the Law The Theology of the Mosaic Law in Hebrews 7:1-10:18 (Eugene, Oregon: Wipf and Stock Publishers, 2009), 138