The English term "testament" comes from the Greek translation of the Hebrew term "berith." "Berith" means "covenant" or "arrangement between two parties," which Moses first mentions of the Torah in Exodus 24:8. While the Abrahamic Covenant encompasses both Old and New Testaments, the Old and New division reflects the covenants that God is abiding by and under which His people are living: the Mosaic Covenant for the Old Testament and the New Covenant for the New Testament.

Thinking that the Old Covenant is in the past and not necessary to read, some Christians just study the New Testament. This is a huge error. Without knowing the Old Testament, you cannot understand the New Testament and appreciate the beauty and elegance of God's logic and plan.

The Bible is essentially about two covenants, the Abrahamic and Mosaic, and how God is faithful to them.

The Abrahamic Covenant, in essence, makes promises to 1) Abraham personally, b) to Abraham's descendants Israel, and c) indirectly to humanity (Gentiles). This covenant forms the basis from which other covenants expand upon.

The Land Covenant (also known as the Deuteronomic Covenant) expands upon God's promise of land. As part of the Abrahamic Covenant, it is unconditional and eternal. This covenant is made with the second generation of Hebrews (descendants of Abraham who inherited his blessing) that came out of Egypt.

Currently, the nation of Israel has not returned to God nor have they obeyed Him, and they only reside in a portion of the Promised Land; hence, the promises of the Land Covenant remain to be fulfilled.

The Davidic Covenant (also known as the King Covenant) expands upon God's promise of a universal blessing that will be a descendant of Abraham. The covenant God made with David (a descendant of Abraham who inherited his blessing) establishes an eternal Kingship that will be inherited from the House of David.

With the birth, death and resurrection of Jesus Christ the Messiah, this covenant has been partially fulfilled. God will fulfill this unconditional promise when Jesus returns.

Like the Davidic Covenant, the New Covenant expands on God's promise of the universal blessing to humanity. This covenant is made with the whole nation of Israel (descendants of Abraham who inherited his blessing). Because of Jesus Christ, it provides the once and for all forgiveness of sins and indwelling of the Holy Spirit.

While it is not apparent in the Old Testament that the spiritual blessings of the New Covenant is available to Gentiles, Jesus Christ introduced the communion cup saying, "This cup which is poured out for you is the new covenant in My blood" (Luke 22:20, 1 Cor 11:25). His reference to the "new covenant" to the Jewish apostles referred to the only "New Covenant" in the Old Testament.

Hebrews refers to Jesus as "the mediator of a new covenant" (Heb 9:15). Because of His sacrifice, the prophecy of Jeremiah is becoming fulfilled, "according to the Law, one may almost say, all things are cleansed with blood, and without shedding of blood there is no forgiveness" (Heb 9:22).

The apostle Paul, former eminent Pharisee of the Jews, in his ministry to the Gentiles, states that Believers are regenerated (Ti 3:5), indwelt with the Holy Spirit (1 Cor 6:19; 2 Cor 3:3), and forgiven of our sins (Eph 1:7; 4:32; Col 1:14).

The Mosaic Covenant (also known as the Law) is a covenant that God made with the Israelites through Moses shortly after they were brought out of Egypt. In contrast to the Abrahamic Covenant, the Mosaic Covenant is conditional and made with the nation of Israel emancipated from Egypt (descendants of Abraham who inherited His blessing). While it appears to be separate and apart from the Abrahamic Covenant, it serves a distinct purpose and becomes part of the Abrahamic Covenant when the New Covenant is initiated.

From an archaeological perspective, the Mosaic Covenant exhibits a structural pattern that is very similar to Hittite Suzerainty Treaties that have been dated from the third millennium B.C to 750 B.C. This type of treaty was made between kings and their vassals, and analogously, the Hebrews were seen as God's vassals. In contrast to the Hittite Suzerainty Treaty, the Mosaic Covenant was public and read every seven years (Deut 31:10-13), and instead of the covenant, God governed the Hebrews. This similarity to the Hittite Suzerainty Treaty provides another piece of evidence that the Mosaic Covenant was made historically during the time of Moses.

The Mosaic Covenant served three purposes:

1. The Law was a system or rules and regulations that God expected of His people, and a violation of the Law was a crime against God (1 Sam 12:9-10). Paul explains that the Law was intended to teach people what sin was (Rom 7:7). Having been slaves and governed by Egypt for hundreds of years, the Hebrews did not know what God's standard for holiness was. The conditional Mosaic Covenant taught them and developed a theocracy that was intended to serve a priestly, rather than political, function.

2. The Law provided a prescribed method of covering and paying for the judicial price of sin for the purpose of restoring a person or people's relationship with God.

3. For those Hebrews who obey God's voice and keep His Covenant, they will be His own possession among all the peoples of the earth, a kingdom of priests and a holy nation (Ex 19:5-6).

The phrase "kingdom of priests" has several interpretations. Many believe this to mean that this nation of priests will mediate the worship of God with the rest of the world. However, this view is confusing in light of the function of Levitical priests who alone mediated for the nation of Israel because of their exclusive access to the Temple where God was.

"The kingdom of priests" can be better understood as a special class of people who are holy and dedicated to serving and worshiping God and not as mediators of anyone. This view is consistent when the New Covenant is initiated (1 Pet 2:4-10).

The Mosaic Covenant was essential to fulfilling God’s promise of land and nation to Abraham; however, it was for descendants who were faithful like Abraham.

In time, Jewish religious leaders perverted the Mosaic Law by adding their traditions to it (Matt 15:1-20) and conditioned obedience to it as the basis for salvation and blessing; instead of portraying the Law as the means to learn about holiness, the Law was portrayed as the primary obligation. Judaism became a religion that emphasized the knowledge and practice of this altered Law as the basis of faith. Despite repeated exhortations of the prophets of God (Isa 1:1-20), Judaism did not realize that Exodus 19:5-6 placed an emphasis on obedience to God’s word not the obligation of sacrifices, rituals, or human intervention.

A Jew who was genuinely obedient reflected a love for God (Deut 6:5) and made the sacrifice that God desired. In similar fashion to Cain (Gen 4:3-5), a disobedient Jew made sacrifices that were not acceptable to God because he did not truly love God with all his heart, soul and mind.

Samuel said, "has the Lord as much delight in burnt offerings and sacrifices as in obeying the voice of the Lord? Behold, to obey is better than sacrifice, and to heed than the fat of rams. (1 Sam 15:22)

The conditional nature of the Mosaic Covenant implies that God anticipated the nation of Israel's failure of upholding their end of the Mosaic Covenant. Paul notes that, "For what the Law could not do, weak as it was through the flesh, God did…" (Rom 8:3). Using Jesus Christ as the mediator of the New Covenant, God accomplishes several important requirements of the Mosaic Law and more:

1. Because the expiation of sin required the blood of an unblemished substitute, Jesus, a sinless human being (John 1:29; 2 Cor 5:21; 1 Pet 2:22-24; 3:18), offered Himself as the guilt offering for mankind's past, present and future sins (Heb 10:12). With the death of Jesus, the sacrifice removed the cause of God's wrath (expiation) and appeased God's judgment (propitiation) of man. Under the Mosaic Covenant, atonement was limited to past sins.

2. Like the Mercy Seat, the crucified Jesus was the place of propitiation (1 John 2:2; 1 John 4:10).

3. As the one presenting the offering, Jesus played the role of the Levitical High Priest (Heb 4:14-16; 8:3; 9:11).

In taking the place of the blood offering, Mercy Seat and High Priest, Jesus Christ replaces all of the required elements involved with the sacrificial system demanded by the Mosaic Covenant. No more sacrifices are possible nor required. Jesus has fulfilled the priestly function of the Mosaic Covenant and is now the only mediator between God and human beings (1 Tim 2:5; Heb 9:15).

With regard to the other purposes of the Mosaic Covenant (i.e. holy behavior / teaching what sin is and qualifying His people), the New Covenant does the following:

1. God will instill His Law within Believers and write It upon their hearts (Jer 31:33). It is a consequence of regeneration, the bestowing of the Holy Spirit within His people (Ezek 36:25-28).

But this is the covenant which I will make with the house of Israel after those days," declares the Lord, "I will put My law within them and on their heart I will write it; and I will be their God, and they shall be My people. (Jer 31:33)

The Hebrew term for "heart" is a reference to the inner being of a person – emotion, cognition, will and consciousness; thus, it is a reference to a person's whole being. In this light, God's people will have a consciousness of God's code of holy behavior.

2. With the start of Jesus' ministry, God gives His people to Jesus (John 6:37-38), and works so that all may believe in whom God has sent (John 6:29). After the crucifixion, Christians are more explicitly identified as "belonging to Christ": (Rom 8:9; 1 Cor 3:23; Gal 3:29; 5:24).

Just as God's own people is a kingdom of priests (Ex 19:6), those that belong to Jesus Christ, will be a royal priesthood and a holy nation (1 Pet 2:4-10). Jesus Christ made Believers to be a kingdom of priests who will serve and worship His Father and be God's own people (Rev 1:6; 5:10).

Initially made as a separate agreement, the conditional Mosaic Covenant revealed to man the impossibility of meeting God's standard of holiness. The subsequent unilateral New Covenant fulfilled the function of the Mosaic Covenant and revealed God's exquisite love for His people and faithfulness to His promises to Abraham which have yet to be completely fulfilled (Matt 5:17-18).