His calling was that of a publican or toll-gatherer to the Romans, a calling held in bad repute among the Jews, for they who practiced it were ordinarily covetous and extortioners, and commonly spoken of as thieves by even the Gentiles.
The Jews, too, felt bitterly aggrieved by the compulsory payment of the tribute-money; it seemed to them an infringement upon their liberty as a free-born people, the privileged people of Almighty God.
It would appear that Matthew was chiefly employed in collecting the duties or customs upon goods coming by the way of the Sea of Galilee, and also in taking the toll or tribute which passengers by water had to pay.
Here then by the seaside, according to St. Mark's account - Matthew, or Levi, dwelt, when our Divine Lord left Capharnaum to walk by the shore while He taught the people who crowded round Him; and seeing Matthew sitting in his custom-house, and said unto him, "Follow Me."
We may suppose that dwelling in Capharnaum, the scene of so many of Christ's miracles, Matthew had heard Him teach, had looked upon His face before that day, perhaps already he had felt drawn by the sweet attraction of the Saviour's look and tone, so that he the more readily became one of the disciples at the Divine call.
Until the Ascension, St. Matthew continued with the rest, but after that time for at least eight years he preached throughout Judea, living an austere life, for according to St. Clement of Alexandria, his usual diet was but herbs, roots, and berries.
Upon Matthew's preparing to commence his labours for the conversion of the Gentiles, the Jewish people begged that he would write out for them the story of Christ's life on earth, so that they might preserve it as a record of all he had preached to them, and in accordance with this desire the Gospel of St. Matthew was composed.
It is recorded that the Apostle converted multitudes by his preaching and his miracles from their idolatry, and then ordained spiritual pastors to watch over them and help them to "grow in grace," finishing his own course by martyrdom in the city of Nakabar.
the Gospel of St. Matthew was first written in Hebrew because originally intended for his own countrymen, but it was speedily translated into Greek.
The Evangelist was careful to prove in his Gospel narrative that Jesus came from the royal family of David, so that the Jews might be convinced, and thus the list of names in the first chapter. Many events are given in it which we do not find in the other Gospels, such as the visit of the Magi to the infant Jesus, and the slaughter of the Innocents.
When St. Matthew is represented as an Apostle, he generally appears as an aged man with a book in his hand, sometimes also with a purse or money-box, in reference to his worldly calling before the day when, by the seashore , he heard the words "Follow Me'" and rising up, quit the service of men for the service of a despised Saviour, yet the Lord of heaven and of earth.
Source: Stories of the Saints, 1874
A coloring picture for the children can be found below.