The two disciples heard him speak, and they followed Jesus.
What seek ye? ... was an appropriate response by Jesus to the fact of their following him; but their response was more timid and hesitant than we might have expected.  Instead of declaring flatly that "We understand that you are the Messiah and would like to follow you," they politely addressed him as "Rabbi," and inquired where he lived!  John's explanation of the term "Rabbi" indicates that the greater part of the Christian world to whom this was written was Gentile.  The hardening of Israel, as prophesied by Jesus and discussed in the writings of Paul, had long ago occurred; and thus the "Jews," as referred to in this Gospel, are to be identified as the unbelieving and antagonistic portion of Israel.