Augustine of Hippo
Catena Aurea · Matthäusevangelium 9
And as Jesus passed forth from thence, he saw a man, named Matthew, sitting at the receipt of custom: and he saith unto him, Follow me. And he arose, and followed him. And it came to pass, as Jesus sat at meat in the house, behold, many Publicans and sinners came and sat down with him and his disciples. And when the Pharisees saw it, they said unto his disciples, Why eateth your Master with Publicans and sinners? But when Jesus heard that, he said unto them, They that be whole need not a physician, but they that are sick. But go ye and learn what that meaneth, I will have mercy, and not sacrifice: for I am not come to call the righteous, but sinners to repentance.
(De Cons. Ev. ii. 26.) Or, perhaps it is more probable that Matthew here turns back to relate something that he had omitted; and we may suppose Matthew to have been called before the sermon on the mount; for on the mount, as Luke relates, the twelve, whom He also named Apostles, were chosen.