John 6:28

Whether this conference was with the Capernaites, in whose synagogue Christ now was, or with those who came from the other side of the sea, is not certain nor material; however, it is an instance of Christ's condescension that he gave them leave to ask him questions, and did not resent the interruption as an affront, no, not from his common hearers, though not his immediate followers. Those that would be apt to teach must be swift to hear, and study to answer. It is the wisdom of teachers, when they are asked even impertinent unprofitable questions, thence to take occasion to answer in that which is profitable, that the question may be rejected, but not the request. Now, I. Christ having told them that they must work for the meat he spoke of, must labour for it, they enquire what work they must do, and he answers them, Joh 6:28, Joh 6:29. 1.

— Matthew Henry's Concise Commentary (public domain)

What shall we do . . . the works of God--such works as God will approve. Different answers may be given to such a question, according to the spirit which prompts the inquiry. (See Hos 6:6-8; Luk 3:12-14). Here our Lord, knowing whom He had to deal with, shapes His reply accordingly.

— Jamieson-Fausset-Brown Commentary (public domain)