Matthew 10:8

Heal the sick, &c. This verse contains the third observation respecting the mission of the apostles: Christ not only gave them power to preach, but also to work miracles, in order, says St. Gregory, that works might give force and efficacy to their words, that as their doctrine was new, so their works might be new, and such as were before unheard of. St. Jerome also says, men would never have given any credit to the apostles, unlearned and illiterate as they were, had they not been able to work miracles in proof of the great promises they made to them of heaven. It was necessary that the greatness of their work should confirm the greatness of their promises. (St. Jerome) --- Gratis you have received. Here our Saviour admonishes his apostles not to work for the sake of lucre; but having themselves received gratuitously the light of faith, they should in the same manner communicate it to others. (St. Jerome) --- St. Aquinas also observes on this passage, that our Saviour probably wished to repress the avarice of Judas, who as he kept the common purse, might be tempted to increase their stock, by receiving pecuniary rewards for their labours. (St. Thomas Aquinas) --- St. Chrysostom says, that the apostles were warned by this admonition of our Saviour against two vices, to which they might be tempted on account of the great favours and graces they had received from heaven, viz. pride and avarice: 1st. Against pride, gratis you have received; i.e. whatever you have received is the gift of God, without any merit of yours: 2ndly. Against avarice, gratis give; that is, since every thing you have received has been given you gratuitously; so if you make use of the same gifts for the good of others, act also gratuitously, without expecting any temporal reward from them. (St. John Chrysostom, hom. xxxiii.)