Who picked the original 12 apostles? Jesus did it himself.
Who picked Mathias? The 11 apostles that remained and then they drew lots on which of the two that they had picked would take Judas place. It is the equivalent of my saying that Lord I picked these two women and I am going to draw lots to see which you want me to marry. What if neither of those two women are what God has for me? I believe that this was the case of the apostles picking the twelfth apostle for Christ.
Jesus picked Paul himself as the 12th apostle, not Mathias. I think that the apostles jumped the gun and pick for Christ. Paul is one of the apostles that is the foundation of the Church.
That is why God gave Paul the same message that He gave the other apostles and Paul preached that message.
GLJCA
I agree with Jesus picking Paul to be [a tag along -johnny-come-lately] witness to the risen LORD; but Matthias is the LORD's pick to fill Judas' place ; for Peter understood the Scriptures and he stood up and quoted them about Judas, and was speaking for the LORD [who gave all His authority to the disciples and told them (all) that whatsoever they bound on earth would be bound in heaven -and so on] when he said they must see whom the LORD would replace Judas with -"let his office another take" to be an eyewitness of Jesus words and life and resurrection.
The office was that of being a companion and eyewitness of all Jesus did and said from the beginnning; Paul actually learned what Jesus said and did by hearsay -from them- and could never have fulfilled that office by any stretch of the imaginatioon; and the Holy Spirit convinced Paul of the truth of what he heard about what Jesus said -as He does us, or else we haven't "seen" him, either.
-and when He was commanded to preach the Gospel that was delivered to him
by Anannais mouth, too, and not by Jesus'.
Paul won't be on a throne 'rulimg the twelve tribes in the millennium, he'll be a stone beside you and me in the House Jesus is building, however -but as a Benjamite Jew He will have a Memorial Gate named after His tribe in the City of God which is New Jerusalem.
Act 1:15¶And in those days Peter stood up in the midst of the disciples, and said, (the number of names together were about an hundred and twenty,)
Act 1:16
Men [and] brethren, this scripture must needs have been fulfilled, which the Holy Ghost by the mouth of David spake before concerning Judas, which was guide to them that took Jesus.
Act 1:17
For he was numbered with us, and had obtained part of this ministry.
Act 1:20
For it is written in the book of Psalms, Let his habitation be desolate, and let no man dwell therein:
and his bishoprick let another take.Act 1:21
Wherefore of these men which have companied with us all the time that the Lord Jesus went in and out among us,Act 1:22Beginning from the baptism of John, unto that same day that he was taken up from us, must one be ordained to be a witness with us of his resurrection.Act 1:23
And they appointed two, Joseph called Barsabas, who was surnamed Justus, and Matthias.
Act 1:24
And they prayed, and said, Thou, Lord, which knowest the hearts of all [men], shew whether of these two thou hast chosen,
Act 1:25
That he may take part of this ministry and apostleship, from which Judas by transgression fell, that he might go to his own place.
Act 1:26
And they gave forth their lots; and the lot fell upon Matthias; and he was numbered with the eleven apostles.
Act 9:6 And he trembling
and astonished said, Lord, what wilt thou have me to do?
And the Lord [said] unto him,
Arise, and go into the city, and it shall be told thee what thou must do.
Act 9:10¶And there was a certain disciple at Damascus, named Ananias; and to him said the Lord in a vision, Ananias. And he said, Behold, I [am here], Lord.
Act 9:15
But the Lord said unto him, Go thy way: for he is a chosen vessel unto me, to bear my name before the Gentiles, and kings, and the children of Israel:
Act 9:17
And Ananias went his way, and entered into the house; and putting his hands on him said, Brother Saul, the Lord, [even] Jesus, that appeared unto thee in the way as thou camest, hath sent me, that thou mightest receive thy sight, and be filled with the Holy Ghost.
Act 9:19
And when he had received meat, he was strengthened. Then was Saul certain days with the disciples which were at Damascus.
Act 9:25
Then the disciples took him by night, and let [him] down by the wall in a basket.
Act 9:26¶And when Saul was come to Jerusalem, he assayed to join himself to the disciples: but they were all afraid of him, and believed not that he was a disciple.
Act 9:27
But Barnabas took him, and brought [him] to the apostles, and declared unto them how he had seen the Lord in the way, and that he had spoken to him, and how he had preached boldly at Damascus in the name of Jesus.
Act 9:28
And he was with them coming in and going out at Jerusalem.
Act 9:32¶And it came to pass, as Peter passed throughout all [quarters], he came down also to the saints which dwelt at Lydda.
BTW -there's Peter out preaching the Gospel outside Jerusalem -another MAD refutation!