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. (Exodus 18:21)
Growth demands change and growth demands expansion. Whatever it took you to get to where you are today, most likely will not get you to where you want to be tomorrow. Moses and Aaron were able to lead the people out of the bondage of Egypt with just the leaders of the twelve tribes. However, they were not able to lead them in the wilderness. They had to change. They had to expand.
When your business, ministry, marriage, family, or whatever endeavor gets beyond your ability, change and expand. Change the way that you are doing things; that is, seek God’s better way. Then, expand, that is, find someone who can take a leadership role with you. Learn to delegate, not just duties, but authority. For example, you will not find in the Bible any church led by just one man. A scriptural church has a plurality of leadership. One person can lead, but not very far and not for very long. Find qualified people to lead alongside you and you will succeed.