I robbed other churches
Meaning the churches of Macedonia; not that what he had of them was by force and rapine, or by plundering of them, and spoiling of their substance, and living upon them against their wills, as soldiers use a conquered people, though the allusion is to such a custom; for what he had of theirs was freely communicated to him; as appears from the following verse: but because these churches from whom he received were poor, and the Corinthians whom he served were rich, he calls it a robbing of the former, though there was no injury in the case, for it was voluntary, because it was expended for the service of the latter:
taking wages of them to do you service;
or "for your ministry"; either to supply their poor, or rather to support the ministry of the Gospel among them. The apostle continues the metaphor, taken from soldiers, to whom wages are due for their warfare; as are also to the ministers of the Gospel, the good soldiers of Jesus Christ; since no man goes a warfare at his own charges and expense but is for by those in whose service he is: and therefore, though the apostle did not think it advisable to ask for, and insist upon wages from them at that time, for his service among them, yet he took it of others in lieu of it; and this he mentions, partly to show that wages were due to him for his ministry, and partly to observe to them who they were beholden to for the support of the Gospel at first among them; as also to stir them up to be serviceable to other churches, as others had been to them.