In Matthew 24:45, "Who then is a faithful and wise servant?" Was Jesus addressing this to a particular group of people or every individual?
Matthew 24 and 25 is the recorded of Jesus teaching his disciples in response to their question: "Now as He sat on the Mount of Olives, the disciples came to Him privately, saying, "Tell us, when will these things be? And what will be the sign of Your coming, and of the end of the age?"" (Matthew 24:3). So the question was directed toward the disciples for their consideration. It is a rhetorical question; that is, a question that is not expecting a vocal answer, but one designed to get the audience thinking about the appropriate response. Thus, the question is, "How can you tell that a servant is a good one -- faithful and wise?" The answer is found in Matthew 24:46, it is the servant who is doing the master's will, even when the master isn't there. Jesus' point is that Christians must always be doing the Lord's will, even if he hasn't returned yet. If someone thinks he can wait until the Lord returns to do right, he is going to find himself in trouble.
See: The Second Coming of the Lord for more on this section of the Gospels.