We have piped. Christ, says, St. Jerome on this place, was represented by the children that piped, or played on pipes, and St. John by those that mourned; because Christ refused not upon occasions, to eat and converse with sinners. (Witham)

Jesus shews the Jews by this simile, that he had endeavoured to induce them, by the common life he led, to an imitation of his virtues; and they had not complied with his desire.

We have lamented. This part is to be understood of St. John, who led a most austere life, and notwithstanding was despised by the Jews. (St. Jerome in St. Thomas Aquinas)

Similar to this is the complaint of the Almighty, by the mouth of the prophet Isaias: What is there that I should have done to my vineyard, and have not done? Our Redeemer and the Baptist imitated skilful huntsmen, who made use of various and opposite stratagems, that if the nimble animal escape one, he may fall into another. As men are commonly more engaged by fasting and austerities, therefore did the Baptist practise them in the highest degree, that they thus might be prevailed upon to believe his words. Christ, condescending more to their weakness, did not embrace this rigid manner of life, though at the same time he sanctified and approved it by his fast of forty days, and extreme poverty, not having where to recline his head. It was better that our Saviour’s doctrine should be approved of by one who practiced austerity, than that he himself should fast and live rigidly. If the Jews admired fasting and penance, whose words should have led them to the Son of God? If fasting appeared sorrowful and forbidding, why did they not join themselves to Jesus, who came eating and drinking, and compassionating their infirmities? which way soever they chose they might have arrived at salvation? (St. Chrysostom, hom. xxxviii.)