NOTES for Mat 17:24-27
The question of paying the tax has several aspects. On the one hand, there is the purely historical and legal aspect, for which modern exegesis offers several interpretations: it may have been the Temple tax established by the Law of Moses, or it may have been a Roman tax, as many Fathers of the Church believed. On the other hand, it is also a spiritual question. We have a firm conception of justice, of what is right and what is not, but we must consider this from an eschatological perspective. Here, within earthly reality, people's concrete needs are more important.
The Lord also shows us how to find the means to meet those needs: earn them through our own labour. A miracle certainly took place here, but Peter was a fisherman; he had to go and cast his line—that is, do his ordinary work—and only then did the miracle happen.