Acts 1:15-17, 20-26 / John 15:9-17
The 12 apostles, as we know were chosen by Jesus. It can be said that they were hand-picked by Jesus.
It was certainly an honour to be in the "original team" and to be associated with Jesus in a special way.
Though Judas Iscariot was one of the original Twelve, he chose to betray Jesus and he met his tragic end and so the apostles were down to Eleven.
The 1st reading recounted how the matter of replacement for Judas was discussed, that Peter and the rest of the disciples prayed, and then cast lots and Matthias was chosen as the replacement and so the the number of apostles were back to 12.
But why is it that the number of apostles can't be 11 and that there must a replacement?
Of course we will remember that the Old Testament Book of Genesis stated there were 12 sons of Jacob and those 12 sons formed the 12 tribes of Israel.
But more than just because Jacob had 12 sons, the number 12 in the Bible signifies perfection of government or rule, and in this sense, it God who has the divine rule of the People of God.
The number 12 has further a significance, as it represents authority, appointment and completeness.
So although St. Matthias is a "replacement" apostle, and not personally chosen by Jesus, he was chosen by the Church community of which Christ is the Head.
It also goes to show that God rules over the Church and that Jesus continues to watch over His Church with the guidance of the Holy Spirit, even though there are times of trouble and tribulation.
For this we give thanks to God and may St. Matthias continue to pray for us that we continue to have faith in the Church as God's appointed means of salvation.