What was the covenant between God and the Israelites?

Answer 1

The answer depends on how far back you would like to go. In essence there were two main covenants involving the nation of Israel. The first would be the Abrahamic covenant established between God himself and Abraham in the year 1943 BCE (at the time known as Abram).

At Genesis 12:1-3 God tells Abraham that he will make him a "great nation" (Israel) and by means of this nation the entire world would be blessed. The specifics of the land that this great nation would inhabit are enlarged upon at Genesis 13:14-18. Note that the Abrahamic Covenant had no "expiration" date, but was to extend through an unspecified period of time until it accomplished the purpose it had been established for: all nations living in blessed harmony with God as stated at Genesis 17:3-8 (incidentally the 17th chapter of Genesis also establishes the Covenant of Circumcision which was a means to identify those who had entered into the covenant made with Abram).

Then there is the Law Covenant established with the nation of Israel and mediated by Moses. After an extend period under the subjugation of Egypt God led the Israelites towards the lands he had promised they would inhabit (by then the Israelites numbered perhaps about 2 million). In 1513 BCE, 430 years after the Abrahamic covenant's establishment, and as we read at Exodus Chapter 17, the nation of Israel agreed to the Law Covenant (often referred to as the Mosaic Law).

The Law was intended for several purposed including: to organize the Israelites as a nation, lead the nation to the Messiah (who would be the key descendant of Abraham that would make it possible for 'all nations to be blessed' ) and to keep them free from pagan practices.

When the Messiah was born into the world his perfect way of living and devotion to God fulfilled the Law. In fact God, through the prophet Jeremiah, had already told the nation that at some time in the future the Law would no longer be in force (Jeremiah 31:31-34). The Messiah's eventual sacrifice made the Law invalid along with its animal sacrifices and ritual atonements. The Christ's blood was worth far more than the blood of the animals upon which the Law was based. Now Christ would act as the mediator between sinners and God (Colossians 2:8-17).

So the Law Covenant came to an end after Jesus sacrifice (see also Matt. 27:51; Mark 15:38; Luke 23:45) but the Abrahamic Covenant continues, again, until its intended purpose has been accomplished: all nations of the world being blessed.

Answer 2

God offered the Israelites protection and a homeland. In return, the Israelites committed to follow God's laws.