Got Question defined the Mosaic covenant as the agreement between God and the  people of Israel. The covenant was made at Mount Sinai, so it is sometimes called the Sinai covenant (Exodus 19—24). God gave the Ten Commandments of the Law to Moses, who was chosen to lead Israel. The Mosaic Covenant was named after him. A Mosaic covenant was a bilateral, or conditional covenant, meaning that both parties were responsible for fulfilling certain duties. God promised to abundantly bless and protect Israel if they followed the Law (Exodus 19:5-8).

Covenant of Grace

An article in Ligonier.org, enumerated the 4 main elements of the Mosaic covenant: 

• The exodus

• The sealing of the old covenant

• The giving of the Law

• The old covenant rituals. 

Exodus demonstrates that the Mosaic covenant is rooted in the covenant of grace. As we read in today's passage, God has made clear that nothing within the Israelites themselves made Him choose the nation and deliver it from Egypt. 

In fact, the Lord chose Israel purely as a result of His benevolence and love, the same love from which He vowed to the prophets (Deut. 7:6–8). This is God's electing grace at work.

It was not necessary that the Israelites obey the Law for the Lord to save them. God rescued His people from slavery before revealing the Law to them (Ex. 20:1–17). It was the Lord's doing that saved the people under the old covenant long before any good works were possible.

The Covenant Is A Law

Christianity.com provided a clear explanation about the Mosaic Covenant. 

Following the promise made to Abraham, the fulfillment appears to be in phases. The truth is, we did not know when the promise first came to Abraham. Yet, God reveals his salvation gradually through history and over time. The first major phase of the fulfillment of that is the call of Abraham's descendants, now the nation of Israel, out of Egypt and into the promised land. These were the beginnings of the fulfillment of the promises to Abraham, including that he would be a father of a great nation and many nations and that there would be a home for them. On the way from Egypt to the promised land, God leads the Israelites to Mount Sinai, where he makes a covenant and said:

 "You will be my people and I will be your God. I have saved you, not because of anything you did, but sheerly out of my grace and love and my promise to Abraham."

Once again the terms of the relationship are set when the covenant is established now with Israel, and we call it the Mosaic covenant. Here, the terms are different. With Abraham, the terms were quite gracious and simple; Abraham just had to believe. The covenant with Abraham was mostly unconditional. The covenant with Moses however was a conditional covenant. Now that you've been saved, God says he wants you to live like his people. To bring glory to my name, I want you to live in such a way that people know you are my people. As a result, He gives the 10 commandments. These represent the terms of the covenant. 

They will be able to remain in the land if they obey, if they keep up their end of this relationship. They will be driven out of the land if they disobey. The covenant is a law. There are things that Israel must do to stay in the land, not to be saved. Blessings come to those who keep the covenant. 

Conditional Covenant Explained

The Mosaic covenant was conditional, unlike the Abrahamic and Davidic covenants, which were unconditional. Under unconditional covenants, God's favor, promises, and blessings are determined by His decision rather than by the actions of the people. Mosaic law stated that a blessing was only to be given if the people obeyed or disobeyed God. Deuteronomy 28.

Why did the gracious God of the New Testament, who loves and forgives unconditionally and offers unconditional salvation, create a conditional agreement in the Old Testament?  

There are several places in the New Testament epistles where the Apostle Paul discusses the old covenant vs. the new covenant. He is referring to the Mosaic covenant, also known as "the Law." The Law's purpose was to make people aware of their inability in order for them to recognize their need for Christ when He arrived(Galatians 3:24-25). Abraham and the other patriarchs were also men of faith who trusted in God rather than in their own works for salvation (Hebrews 11:4-12). Hence, the fact that there is a Mosaic covenant does not contradict God's grace, rather it emphasizes our need for that grace (Ephesians 2:8-9; Romans 1:16-17). For more details, visit Completing Truth.

The primary reason that the Mosaic Covenant was conditional was because as mentioned above the purpose of the agreement was less about salvation and more about their mission. They were to be a kingdom of priests, a witness to the nations, a microcosm of the Kingdom of God. The goal was that the nations would see what a relationship with the true God looked like and want to join in. If the people were not following God and God continued to bless them the onlooking nations might get the wrong Idea and think sin was ok with God, that the other Gods like Baal and Ashera that the Isrealites were worshiping in sin were the true Gods and it was ok to follow them. God couldn’t begin to reverse the curse brought in by Adam and Eve and Israel couldn’t lead the way, If they themselves were continuing to walk in evil ways. 

The Five Divine Promises It Holds

The overview of how the covenant was established between God and Israel allows us to answer the questions: 

• What are the covenant's divine promises and human conditions? 

• Is God obligated to do anything? 

• What does He expect from his partner in the covenant?
  

Below are the five divine promises within it as written by John Piper in Desiring God: 

• Israel will be God's special possession.

• Israel will be a kingdom of priests to God.

• Israel will be a holy nation.

• God will fight for Israel and overcome all her enemies.

• God will treat Israel with grace and mercy and forgive her sins.
  

In summary, the divine covenant has these promises. They are all dependent upon the people fulfilling certain conditions. 

 "If you will obey my voice and keep my covenant, then you shall . . . " experience all these divine blessings.  Exodus 19:5