Under the dispensation of promise all that was required of the Israelites was that they trust God to do as He had promised. They failed in this and the law was introduced. Man’s conscience had failed him already as wickedness abounded in the time before the flood. Likewise, man was incapable of governing himself, so God imparts His laws to His people.
God’s laws are not given as a burden or punishment however. They serve three purposes. First was that they were given to protect the people just as a parent forbids a children from a dangerous activity for their own good. Second, the sacrificial system pointed to Jesus and every detail had a purpose in portraying the coming Messiah. And third, the law was meant to show the Israelites that they were totally incapable of living up to God’s standards and were thus in need of a permanent solution for sin – Jesus’ death on the cross.
The Mosaic covenant can be broken into three parts. First is the commandments; this obviously includes the Ten Commandments, but also the many rules for day to day living that were handed down to Moses by God. The second part is judgments. These were not just what the lawbreaker should expect as punishment from God as was the case in previous covenants. This also outlined what human governments should do as punishment for various offenses. The third part is ordinances that instruct the people how to properly remember the Lord and worship Him.
The three parts of the Mosaic covenant address the failures of the three previous dispensations. Because man was unable to follow his conscience, God gave specific rules to be obeyed. Because man was not able to govern justly, God gave specific punishments for failure to uphold the law. And because man was unable to see God’s plan at work and to trust Him, God gave specific religious instructions that were meant to point to the coming Messiah.
The dispensation of law failed worse than the previous dispensations. Not only did the fixes to the previous dispensations not work, the Israelites missed the point in the law itself. Rather than pointing them to their need for a Messiah, the people became self righteous. When Jesus came, He frequently butted heads with the Pharisees who believed that they were righteous because they followed the law and added more laws to what God had given them. They missed the fact that no one was capable of following the law and needed Jesus!