V. Was Peter therefore right in assuming that Judas must be replaced? (Acts 1)
Peter knew, instinctively and/or from the Spirit of God, that the number of apostles was to be twelve. Now, we know what Peter did with that instinct.
First, we know he felt an urgency to get the number back to twelve, to fill the vacated office of Judas. His logic and motivation as he addressed the others was impeccable. He correctly interpreted Psalm 69:25, that Judas' office was to be taken by another.
Then he described the parameters of that office by saying it must be filled by one who had accompanied the apostolic band during the life of Jesus, and who had been a witness of the resurrection.
Using these guidelines, which may have been Peter's, and not necessarily the risen Lord's, two men were set forward as candidates. A prayer was offered, asking that the Lord would show which of the two He had chosen.
Then instead of waiting for a Divine confirmation for one of them, the group in authority resumed a practice that had been used from the days of the wilderness through the times of the prophets: the casting of "lots." This was simply throwing some stones out to see what "chance" would say.
There is of course Biblical backing for such a practice, beside the accounting of persons who did it. The Proverbs are clear:
"The lot is cast into the lap, but its every decision is from the Lord." (Proverbs 16:33)
"Casting lots causes contentions to cease, and keeps the mighty apart." (Proverbs 18:18)
The idea is that this method of decision-making is impartial, not able to lend itself to human opinion, a type of trusting of the Lord.
Peter's faith was moving as quickly as it could, but as in other statements and actions of dear Peter, it seems he may have misjudged the season. A new thing was coming. He had no idea just how new it would be.
VI. So was Matthias the 12th apostle?
You will note, that this Acts 1 accounting of "lots", before the initiation of the Spirit's reign in the very next chapter of Acts, is the last mention of this practice in the New Testament, either by example or direction.
It seems to me that Peter was acting in the best of traditions, with the highest of motivations, but perhaps without the full knowledge of what the Spirit wanted in this matter. Seeing the dramatic calling and subsequent ministry of one Saul of Tarsus unfold in chapters to come leaves one thinking that Matthias was probably not the man to become one of the foundational apostles of the church, but served as a place-holder until Paul's conversion.
The death of James, the brother of John, while Paul is in training, thus bringing the number back to eleven, leads one also to believe that Paul was to be number twelve, in a literal and necessary sense. James dies in chapter 12. Saul, a teacher up until now, is first sent out on an apostolic mission in chapter 13.
I do not suggest that this was the thinking of the apostles still living. Paul was opposed by much of the leadership at first. But God knows who His men are, and their place in the church. Even today there are those called pastors who are not, and not called pastors, who are. Just as the church itself is "invisible" in its boundaries, so often is its leadership.