Acts 6

As the converts continued to increase in the primitive Church -

"...in those days, when the number of the disciples was multiplied, there arose a murmuring of the Grecians against the Hebrews, because their widows were neglected in the daily ministration.
2 Then the twelve called the multitude of the disciples unto them, and said, It is not reason that we should leave the word of God, and serve tables.
3 Wherefore, brethren, look ye out among you seven men of honest report, full of the Holy Ghost and wisdom, whom we may appoint over this business.
4 But we will give ourselves continually to prayer, and to the ministry of the word."  (New Testament | Acts 6:1 - 4)

For the first time, we see the need for additional officers in the Church.  In this case "Seven" which I believe were those that would eventually lead the seventy.  I note the condition for those to serve in offices of the Church include honesty, wisdom, and full of the Holy Ghost, for it is the Holy Ghost that will lead them in their calling to do the will of the Father.

Just another thought.  Stephen mentioned that -

"...when he was full forty years old, it came into his heart to visit his brethren the children of Israel.
24 And seeing one of them suffer wrong, he defended him, and avenged him that was oppressed, and smote the Egyptian:
25 For he supposed his brethren would have understood how that God by his hand would deliver them..."  (New Testament | Acts 7:23 - 25)

It appears to me that Moses, from prophecies of Joseph, already understood his mission and that he would deliver Israel for Joseph testified -

"...Moses, whom I have said I would raise up unto you, to deliver my people, O house of Israel.
10 And Moses will I raise up, to deliver thy people out of the land of Egypt."  (Book of Mormon | 2 Nephi 3:9 - 10)

Israel and Moses's mom were probably more than familiar with this prophecy.