The writer of the book of Hebrews makes known that the priest-hood of Jesus has changed. “For the priesthood being changed, there is made of necessity a change also of the law” (Heb. 7:12). The Old Testament priesthood descended through the lineage of Aaron. His descendants were assisted in their ministry at the altar by the other descendants of the tribe of Levi.
However, Jesus was from the tribe of Judah. From the standpoint of the Old Testament, Jesus could not serve as a priest. “For it is evident that our Lord sprang out of Judah; of which tribe Moses spake nothing concerning priesthood.” Hence, if Jesus is a priest today, then the law must have changed. Hebrews reveals that Jesus is our high priest and that his priesthood is after the order of Melchizedek, rather than a Levitical priesthood. “Seeing then that we have a great high priest, that is passed into the heavens, Jesus the Son of God, let us hold fast our profession. For we have not an high priest which cannot be touched with the feeling of our infirmities; but was in all points tempted like as we are, yet without sin” (Heb. 4:14-15). As he saith also in another place, “Thou art a priest for ever after the order of Melchisedec” (Heb. 5:6). Knowing that Jesus is our great High Priest, we conclude that we are living under a different law from the Old Testament, the Law of Moses.
Differences In The Two Covenants
Because the law has changed there are many differences between the Old Testament and the New Testament. Here are few of them:
The sacrifice is different. The Old Testament commanded that the blood of bulls and goats was to be offered on a literal altar for sin. It was made known the impossibility of blood of bulls and goats to take away the sins of the world. (Heb 10:4) Under the New Testament, the blood of Christ was shed once for all times on the cross of Calvary as an atonement for the sins of men under both covenants.
The priesthood is different. The Old Testament legislated a separate priesthood that was passed down to the descendants of Aaron. Under the New Testament, every Christian is one of God’s priests. We are a royal priesthood (1 Pet. 2:9) offering our spiritual service to God (Rom. 12:1-2).
The worship is different. Under the Old Testament, the Law allowed for a separate group of singers who used mechanical instruments of music in worship to God. The Scriptures declare, “And he set the Levites in the house of the Lord with cymbals, with psalteries, and with harps, according to the commandment of David, and of Gad the king’s seer, and Nathan the prophet: for so was the commandment of the Lord by his prophets” (2 Chron. 29:25). The use of mechanical instruments of music in the Christian dispensation is without divine authority.
Furthermore, there is nothing in the Old Testament that corresponds with the Lord’s supper. Jesus instituted the Lord’s supper on the night he was betrayed. The Lord’s supper was not a part of the Old Testament worship. Prayer in the name of Jesus was not a part of the Old Testament worship. Jesus said, “Whatsoever you shall ask the Father in my name, he will give it you. Hitherto have you asked nothing in my name: ask, and you shall receive, that your joy may be full” (John 16:23-24). The manner of funding God’s worship has changed from tithing to a free-will offering (1 Cor. 16:1-2). The preaching of apostolic doctrine” was not a part of the Old Testament (cf. Acts 2:42). Jews were to assemble on Sabbath day to remember how God delivered Israel from the bondage of the Egyptians. Christians are to assemble each Lord’s day, Sunday, to remember the Lord’s death, burial, and resurrection. (1 Cor 11:24-26)
God’s marriage laws are different. The Old Testament allowed men who participated in polygamy to be received into the fellowship of God and his people. In the New Testament, the Lord instructed, “Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband” (1 Cor. 7:2). No one could serve as an elder or deacon, but those who were the husband of one faithful and submissive wife (1 Tim. 3:2, 12).
There were other Old Testament legislation’s that are not a part of the New Testament law of marriage. Here are some Old Testament laws on marriage that are not duplicated in the New Testament: (a) A priest could not marry a prostitute or a divorced woman (Lev. 21:7); (b) One who falsely charged that his wife was not a virgin when they married could never divorce his wife (Deut. 22:19); (c) One who committed fornication with a woman who is not betrothed was fined 50 shekels, married the woman, and could never divorce her (Deut. 22:28-29); (d) If one divorced his wife and she married another, he could never have her again as his wife, even if her second husband died (Deut. 24:1-4); (e) Adulterers were to be put to death (Lev. 20:10).
When Jesus preached the Sermon on the Mount, he outlined His authority to make the change in the laws. He not only merely changed it, he took the old law out of the way and nailed it to His cross. This is the same law which Jeremiah the prophet prophesied would end and be replaced with a new covenant, or testament. (Jer 31:31-34) Jesus stripped the marital law down to its core, that is, the heart. He took away revenge and kept that privilege for himself. Thus, man was made to turn the other cheek.
Conclusion: We need to remember the fundamental themes of the Bible, one of which is that in these days, God speaks to us through his Son. “God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets, hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds” (Heb. 1:1-2). The differences in the two covenants were too great to blend them together as one new law. The bottom line is: We are no longer living under Old Testament law of Moses, but are fully under the New Testament law of Christ.