Through a dream, the Lord showed me that Aaron had to wait longer than Moses to fulfil his calling. He showed me that the first reason Aaron had to wait longer than Moses was firstly because he was three years older than Moses.
Moses was eighty years old, and Aaron was eighty-three when they made their demands to Pharaoh. (Exodus 7:7, NLT)
By virtue of being older, Aaron had to wait (at least) an extra 3 years. However, the main reason Aaron had to wait longer than Moses to fulfil his calling was because Aaron couldn’t begin his call until Moses had fulfilled his.
Aaron’s call was to the priesthood. Yes, he assisted Moses in the delivery of the children of Israel from Egypt, and yes, He acted as Moses’ spokesman and performed the miracles God commanded on Moses’ behalf; however, all of that was a part of Aaron’s process. If he did not help Moses to fulfil his assignment to deliver the children of Israel from Egypt, through the Red Sea and then remained present whilst Moses went up Mount Sinai to receive the law, commandments and pattern for the tabernacle (granted his golden calf making wasn’t a great move - see Exodus 32), then Aaron would never have been able to fulfil his call (his destiny) as a priest of God when the time came.
And take thou unto thee Aaron thy brother, and his sons with him, from among the children of Israel, that he may minister unto me in the priest's office, even Aaron, Nadab and Abihu, Eleazar and Ithamar, Aaron's sons. And thou shalt make holy garments for Aaron thy brother for glory and for beauty. And thou shalt speak unto all that are wise hearted, whom I have filled with the spirit of wisdom, that they may make Aaron's garments to consecrate him, that he may minister unto me in the priest's office.(Exodus 28:1-3, KJV)
Both Aaron and Moses were called by God to the same people group; however, Aaron had to first support Moses’ ministry (as part of his process) before he would be able to fulfil his own. Moses also had his own process but his involved life as a prince in Egypt, then serving under Jethro in Midian.
Moses and Aaron were both called by God, but God's order required Moses' work to come first. Moses got to speak to God face to face (Exodus 33:11, Numbers 12:8), but Aaron got to go into the Holy of Holies (Leviticus 16:2-3). Both had their process and both had their privileges.
BRINGING IT BACK TO YOU
So, perhaps you’re working/serving alongside someone that is reaching the same people group that you know you are called to reach? Perhaps at the moment you serve under their ministry or are known primarily through their name? Perhaps you feel like the Lord is never going to release you into your own name or to fully operate in your own lane? Have you ever considered that you are an Aaron?
Aaron was called to serve the same people as Moses was; nevertheless, Aaron could not fully step into his call/destiny until he helped Moses to fulfil his. Aaron was also a leader, but his process required him to firstly serve his people actively and visibly under Moses' vision, under Moses' leadership. Aaron had to endure his process until the Lord was ready to establish and release him into his unique office within the pattern revealed to Moses.
If you are an Aaron, the Lord has called you to work within the vision of another. Yes you are a leader, and yes, the Lord has a unique division in store for you to lead; nevertheless, you will have to serve humbly until the Lord is ready to reveal the specifics of the plan He has for you. Before you can fulfil your predestined work, you will firstly need to help your Moses to fulfil theirs.