John Chrysostom

Great is the force of virtue that makes the rich seek the way of salvation from the poor, from him that hath nothing.

Catena Aurea by Aquinas ↗

Theophylact of Ohrid

He persuades the tax collectors not to overcharge, that is, not to demand anything extra.

Commentary on Luke ↗

Bede

Then publicans also came to be baptized and said to him: Master, what shall we do? And he said to them: Do nothing more than what is appointed to you. The great power that the word of the blessed Baptist had and how much it stirred the minds of the hearers is proven here, as it compelled even the publicans and soldiers to seek counsel for their salvation. To whom he, no differently than to the crowds, advises the practice of mercy according to their appropriate situation. …

On the Gospel of Luke ↗

Bonaventure

Secondly, to the publicans seeking instruction, he gives a lesson about keeping the laws, when it is added: And the publicans also came to him, to be baptized. "Publicans were those who collected public taxes, or who were contractors of the revenues of the treasury, or of public affairs," or who received the royal taxes in a lump sum. …

Commentary on Luke, Chapter 3 ↗