"Leviticus 26:12 And I will walk among you, and will be your God, and ye shall be my people.
Exodus 19:1 In the third month,
when the children of Israel were gone forth out of the land of
Egypt, the same day came they into the wilderness of Sinai.
The Covenant to the Israelite people was a marriage between God and his chosen people. The Bible says that God laid out before them a covenant that if they would keep it, they would be a peculiar treasure unto Him, they would be his people and they would be a kingdom of priests and a holy nation.
What is the basis of this covenant?
The basis of the covenant is the Moral Law, the Ten Commandments, which is God's universal governing law. It is this law that the statutes and the Civil Laws of Israel extended harmoniously from, by the word of God given to Moses. Soon after the encampment at Sinai, the Israelites were told to prepare for two days and on the third day God appeared in person on top of Mount Sinai and proclaimed the Decalogue in a mighty audible voice. Then Moses was called up into the mountain to meet with God. Alone he climbed the steep and rugged path, and drew near to the cloud that marked the place of Jehovah's presence. Israel was now to be taken into a close and peculiar relation to the Most High; to be incorporated as a church and a nation under the government of God. They were the covenant people, different from all the people of the world, based on keeping God's ten commandments.
The whole covenant is found in Exodus Chapter 20 to 24.