A number of covenants are enumerated in the Old Testament. One of the first ones was God’s simple covenant with Abraham in Genesis 12, when God told Abraham that he would make of him a great nation and that Abraham and his descendants were to be a blessing to others. Apparently, the covenant with Abraham was too simple.
In time, there was a covenant or many covenants contained in the Law of Moses, generally regarded as the first five books of the Old Testament, the Pentateuch or Torah. This covenant was much more detailed and complicated. It was in part ceremonial, containing instructions about priesthood duties, rituals, and various kinds of sacrifices. Tacked on to the Torah was what is usually called the Oral Torah, adding more details that governed almost every aspect of life.
Surely realizing that the Mosaic Law was so complex and rigid that it had become form over substance, God said through Jeremiah that a time was coming when he would make a new covenant. “I will put my law in their minds and write it on their hearts.” (Jeremiah 31:31-34) The writer of Hebrews quoted Jeremiah when he proclaimed that the new covenant had been established and that Christ was the mediator of this covenant–“now that he has died as a ransom to set them free from the sins committed under the first covenant.” (Hebrews 8:8-12, 9:15)
Hebrews 8 confirms what Jesus himself said in Luke 22:20: “This cup is the new covenant in my blood, which is poured out for you.” In Ephesians, Paul identifies this new covenant as a gift from God: salvation by grace–not by works. (Ephesians 2:7-9)
I may be wrong, but it seems that ever since the new covenant was written on our hearts through Christ’s death, we have been hard at work to complicate the new covenant, just like the Israelites did with the old one.