Since this request for proof is undoubtedly coming from a beloved Protestant brother, it would do well to look into the Holy Scriptures. Two very great and shining examples immediately jump to mind: in the book of Numbers, and in the book of Acts.
In the book of Numbers 27:12-23, Moses is near to death. After having sorted through marriage and inheritance laws, our Lord commands Moses to appoint a successor. The patriarch is reminded, by God, that he has no right to see the promised land because of his iniquities in the desert and his lack of fortitude in doing God’s will, at times. The Lord gives Moses chastisement for these things, but also has mercy on Israel because of His glorious plan for humanity. The great Immortal One tells Moses to go up to a high place before all the people and elders of Israel, and to
lay his hands upon Joshua, saying “all that the Lord tells you”. When Moses did these things, Joshua became the “next Moses” and received all the power, gifts, and abilities from God that Moses had possessed.
Later, in the New Testament, our Lord Jesus Christ made reference to this metaphorical seat of Moses that passes down all the way from Moses, through Joshua, to the Pharisees of our Lord’s day. He said “do what they say, not what they do; for they sit in the seat of Moses”, as authority. This is taken from Numbers 27!
In the book of Acts of the Apostles 1:15-26, we hear of the days before Pentecost, where the infant Church was hiding and making its plans. St. Peter stands amongst them in the Upper Room and says that, as the Lord had commanded, there must be twelve Apostles among the disciples and with them. He specifically places the Apostles above the rest, though in honour and power given by God and not as “better men”. The first Pope very strongly stresses the need for exactly twelve Apostles to be had. Since Judas was gone, and out of sorrow committed suicide, Matthias was chosen by lots. Matthias filled a special place that had been lost, and entered into a gap that had been created by the death of Judas.
This second scriptural passage illustrates the need for specific Apostles. It grew over time, but was never under 12.
