By the sea-side - That is, by the Sea of Tiberias, on the shore of which Capernaum was situated. See the notes at Matthew 4:13.

(2) And he went forth again by the sea side; and all the multitude resorted unto him, and he taught them.
(2) The gospel offends the proud and saves the humble.

And he went forth again by the sea side,.... The sea of Galilee, where he had met with, and called Peter and Andrew, James and John; and not far from which were the solitary place, and the desert places, where he was before he entered into Capernaum:
and all the multitude resorted unto him; who had been with him at Peter's house, and about the door, and those who could not get near him:
and he taught them; the word of God, the Gospel, and the doctrines of it.

Matthew was not a good character, or else, being a Jew, he would never have been a publican, that is, a tax-gatherer for the Romans. However, Christ called this publican to follow him. With God, through Christ, there is mercy to pardon the greatest sins, and grace to change the greatest sinners, and make them holy. A faithful, fair-dealing publican was rare. And because the Jews had a particular hatred to an office which proved that they were subject to the Romans, they gave these tax-gatherers an ill name. But such as these our blessed Lord did not hesitate to converse with, when he appeared in the likeness of sinful flesh. And it is no new thing for that which is both well done and well designed, to be slandered, and turned to the reproach of the wisest and best of men. Christ would not withdraw, though the Pharisees were offended. If the world had been righteous, there had been no occasion for his coming, either to preach repentance, or to purchase forgiveness. We must not keep company with ungodly men out of love to their vain conversation; but we are to show love to their souls, remembering that our good Physician had the power of healing in himself, and was in no danger of taking the disease; but it is not so with us. In trying to do good to others, let us be careful we do not get harm to ourselves.

All the multitude came to him - Namely, by the sea side. And he as readily taught them there as if they had been in a synagogue.