Elected Apostle?

Then they returned to Jerusalem from the mount called Olivet, which is near Jerusalem, a Sabbath day’s journey away. When they had entered the city, they went up to the upper room where they were staying; that is, Peter and John and James and Andrew, Philip and Thomas, Bartholomew and Matthew, James the son of Alphaeus, and Simon the Zealot, and Judas the son of James. These all with one mind were continually devoting themselves to prayer, along with the women, and Mary the mother of Jesus, and with His brothers.
At this time Peter stood up in the midst of the brethren (a gathering of about one hundred and twenty persons was there together), and said, “Brethren, the Scripture had to be fulfilled, which the Holy Spirit foretold by the mouth of David concerning Judas, who became a guide to those who arrested Jesus. For he was counted among us and received his share in this ministry.” (Now this man acquired a field with the price of his wickedness, and falling headlong, he burst open in the middle and all his intestines gushed out. And it became known to all who were living in Jerusalem; so that in their own language that field was called Hakeldama, that is, Field of Blood.) “For it is written in the book of Psalms,
‘LET HIS HOMESTEAD BE MADE DESOLATE, AND LET NO ONE DWELL IN IT’;
and,
‘LET ANOTHER MAN TAKE HIS OFFICE.’
Therefore it is necessary that of the men who have accompanied us all the time that the Lord Jesus went in and out among us— beginning with the baptism of John until the day that He was taken up from us—one of these must become a witness with us of His resurrection.” So they put forward two men, Joseph called Barsabbas (who was also called Justus), and Matthias. And they prayed and said, “You, Lord, who know the hearts of all men, show which one of these two You have chosen to occupy this ministry and apostleship from which Judas turned aside to go to his own place.” And they drew lots for them, and the lot fell to Matthias; and he was added to the eleven apostles. Acts 1:12-26

Peter took charge. The Lord had ascended, with instructions for the disciples to wait together for the Holy Spirit baptism. The whole assembly of about 120 believers stayed together and prayed, as they waited. Interestingly, Jesus' brothers were mentioned among the believers. Notice these people were all "of one mind" in their devotion and prayer. The brothers had not believed in Him before the crucifixion (Mark 3:20-21, John 7:5). No doubt, He had been an embarrassment to his natural brothers. He must have been perceived by them as the oddball in the family. Perhaps more than a little different. In Matthew 10:34-38 Jesus had spelled out the conflict that would occur in families because of Him, stating that a man's enemies would be the members of his household. There is no mention of brothers at the cross; but here, 40 days later, they are meeting and praying "of one mind" with their mother and the other believers. Praise God! They finally understood. There's hope for your family, too.

Peter announced that they must replace Judas, who had gone his way "to his own place." He asked for nominations of men who had been with them throughout Jesus' ministry, death and resurrection. An apostle must be an eyewitness of the risen Christ. They nominated two, prayed for God's choice and drew lots. Matthias was chosen and added to the roster, making them Twelve again.

And that is ALL we know about Matthias. Jesus, Himself was not present there and the Holy Spirit had not yet been given. Matthias was probably a good and faithful disciple, but after his election as an apostle, there is no further mention of his name.

There was to come, in Acts 9:15-16, the account of Jesus' appointment of His Own choice to be His apostle "...he is a chosen instrument of Mine, to bear My name before the Gentiles and kings and the sons of Israel; for I will show him how much he must suffer for My name’s sake.” None other than Saul of Tarsus, who had savagely persecuted the Church as a legalistic Pharisee, before the risen Jesus clobbered and subdued him on on the Damascus road.