John Chrysostom — as excerpted in the Catena Aurea on Matthew 10:9-10

“It behoved the Apostles to be supported by their disciples, that neither they should be haughty towards those whom they taught, as though they gave all, and received nothing; and that the others, on their part, should not fall away, as overlooked by them. Also that the Apostles might not cry, He bids us lead the life of beggars, and should be ashamed thereat, He shews that this is their due, calling them labourers, and that which is given their hire. For they were not to suppose that because what they gave was only words, therefore they were to esteem it but a small benefit that they conferred; therefore He says, The labourer is worthy of his meat. This He said not to signify that the labours of the Apostles were only worth so much, but laying down a rule for the Apostles, and persuading those that gave, that what they gave was only what was due.”