Exodus 4:29

And Moses and Aaron went and gathered together all the elders of the children of Israel:

Moses and Aaron came together again in the mount of God after many years of separation, Aaron being three years older than Moses. God had chosen Aaron to be with Moses in the deliverance of Israel and to listen to his words, giving Moses words to tell Aaron what part he should act. Angels had instructed Moses concerning the work he was to perform, and angels were also sent to direct Aaron to go into the wilderness to meet Moses. After that meeting Moses told Aaron all the words of the Lord who had sent him and all the signs He had commanded him.

After arriving in Goshen in Egypt, Moses and Aaron went and gathered together all the elders of the children of Israel. The purpose was for Aaron to speak to the elders all the words the Lord had spoken to Moses and to do the signs in the sight of the people, telling what God had said and done for Moses. By this the elders and the people were introduced to God's message of deliverance. When they heard that the Lord had visited Israel and looked upon their affliction, the people believed and bowed their heads and worshiped.

This gathering with the elders to deliver God's message was an attempt to reform the people that increased their oppression. The release sought in this mission was necessary so Israel could serve God by keeping His statutes, including the Sabbath. Their deliverance placed them under special obligation to keep the commandments and to show kindness to the stranger, the fatherless, and the widow.