God told Moses the laws that were to be applied to the people. God instructed Moses on how to build a Tabernacle and an Ark (Exodus 25:10: of acacia wood, 3 3/4 ft. long, 2 1/4 ft. wide, 2 1/4 ft. high overlayed with gold (inside and out) containing inside the stone tablets engraved with the Ten Commandments). The Ark would be a place in the Holy of Holies for God to reside. Aaron and his sons were designated as the priests for God. The requirements for altars, incense, and offerings were described to Moses by God. Moses first went to Mt. Sinai to get the Ten Commandments and was there for 40 days and 40 nights. Since Moses was gone so long, his brother, Aaron, at the request of the people built a golden calf that they all worshipped. Moses saw this and, in disgust, destroyed the stone tablets of the Ten Commandments that God had given to him. He then went back to Mt. Sinai for another 40 days and 40 nights and made a contract (or Covenant) with God to not destroy the people if they would obey the Ten Commandments.
In Exodus 18.13 we read, "And it came to pass on the morrow, that Moses sat to judge the people: and the people stood by Moses from the morning unto the evening." And Moses said to his father in law, 'Because the people come to me to inquire of God. When they have a matter, they come to me; and I judge between one and another, and I make them know the statutes of God and his Laws ..Exodus 18.15-16 ".. Jesus plainly said they were to observe and do what the scribes and Pharisees said but to beware of the doctrines of men which are added to the Laws of God!
Jethro's advice to Moses
And so it was, on the next day, that Moses sat to judge the people; and the people stood before Moses from morning until evening. So when Moses' father-in-law saw all that he did for the people, he said, "What is this thing that you are doing for the people? Why do you alone sit, and all the people stand before you from morning until evening?" And Moses said to his father-in-law, "Because the people come to me to inquire of God. When they have a difficulty, they come to me, and I judge between one and another; and I make known the statutes of God and His laws."
So Moses' father-in-law said to him, "The thing that you do is not good. Both you and these people who are with you will surely wear yourselves out. For this thing is too much for you; you are not able to perform it by yourself. Listen now to my voice; I will give you counsel, and God will be with you: Stand before God for the people, so that you may bring the difficulties to God. And you shall teach them the statutes and the laws, and show them the way in which they must walk and the work they must do. Moreover you shall select from all the people able men, such as fear God, men of truth, hating covetousness; and place such over them to be rulers of thousands, rulers of hundreds, rulers of fifties, and rulers of tens. And let them judge the people at all times. Then it will be that every great matter they shall bring to you, but every small matter they themselves shall judge. So it will be easier for you, for they will bear the burden with you. If you do this thing, and God so commands you, then you will be able to endure, and all this people will also go to their place in peace."
So Moses heeded the voice of his father-in-law and did all that he had said. And Moses chose able men out of all Israel, and made them heads over the people: rulers of thousands, rulers of hundreds, rulers of fifties, and rulers of tens. So they judged the people at all times; the hard cases they brought to Moses, but they judged every small case themselves. Then Moses let his father-in-law depart, and he went his way to his own land.