2 Peter 3:11

11 Since all these things are to be destroyed in this way, what sort of people ought you to be in holy conduct and godliness,

These words are meant not as a question but as an exclamation. Peter is saying that in light of their disastrous future, they ought to be a godly people with holy conduct, for two reasons: 1) to show to God their trust and love for Him; and 2) so that others in the world will see their courageous faith and will desire to be like them.