The holy relationship between humanity and G-d is based, according to Judaism, on the 3 covenants which are found in the Torah:
- Noah: Found in Genesis 9, this first covenant was between G-d and all of humanity, when He told Noah that He would honour human life as sacred (hence, no more earth-encompassing floods!), and the sign of this covenant was the rainbow.
- Abraham: Found in Genesis 17, the second covenant was narrowed down to a promise between G-d and the descendants of Abraham. See, first G-d told Abraham to kill his first born son, and because Abraham was about to obey G-d, He decided to reward His faithful servant by stating that the progeny of Abraham would number more than the stars in the sky, that they would inherit the land of Canaan, and that his other son Ismael would get some action as well. Sign of the covenant- circumcision (the Hebrew word is Berit Milah, or 'covenant of our father Abraham').
- Moses: See Exodus 19. The final covenant (according to Judaism) was once more narrowed down, to include G-d and the Israelites- His chosen people, who were to be Qadosh, or holy and set apart, to be light to the people (Or Laguyim). This is also known as the Sinaitic Covenant, and the sign of the covenant is the Torah. The promise? That the Israelites were to inhabit the land of Israel, the land 'flowing with milk and honey' (Deuteronomy 26), as long as they follow His mitzvot (laws/commands): "You shall be to Me a kingdom of priests and a holy nation."-Exodus 19
In the ancient world, there were two main types of treaties- a bilateral, or Parity treaty, and a unilateral, or Suzerainty treaty. The Parity treaty was between two equals, and an example of this in the Old Testament is the treaty between Jacob and Laban in Genesis 31. It is basically a mutually advantageous political alliance. On the other hand, the Suzerainty treaty was between a king and his vassals, and it was generally imposed upon the subjects, telling them what was expected from them, and what they could expect from their king.
In the Greek Old Testament, the words used to describe these two different treaties are diatheke (a covenant between G-d and man) and suntheke (a contract). The suntheke, or parity treaty, first presents the law or imperative, and if this law is not followed, the indicative (statement of fact) is void. In other words, I might make a bilateral parity contract with a business partner saying that if we both contribute x amount of resources, then we can be partners and share the profit. However, if the rules are broken, the contract is void. On the other hand, the diatheke is a unilateral covenant, similar to the Suzerainty treaty, which first presents the indicative: I am the Lord your G-d, then the imperative: You shall have no other gods before me and then a blessing or curse is at the end. This blessing/curse describes the consequence of one's decision to reject or accept the imperative, without changing the original indicative, but abandonment is never the option.
In other words, the indicative (G-d's nature, His love for us) will never change, even if we do not follow the law. Yes, there will be a consequence, but G-d is shown to be a fundamentally indicative G-d-- not an imperative G-d who is boxed in by His own rules.
The Old Testament is not synonymous with legalism. Legalism says "if you keep the law, G-d will love you," with love being the reward. This is not what YHWH Elohim of the Old Testament is about.