The rooster can crow till the cows come home but the days of denying Jesus are over for Peter. When one is filled with the Holy Spirit there is no room for fear and so the Peter who formerly wept bitter tears is now the Peter who publicly stands on Christ the Cornerstone and declares what he previously denied. Of course Peter is seeing things in light of the resurrection which gives him a confidence he didn't have in the courtyard. We are not nearly as hard pressed as Peter to publicly declare something that in the end led to his imprisonment and crucifixion but we are called none-the-less to be public about our faith in the name by which we are saved. That doesn't mean we are called to stand on street corners with signs. But if we truly believe in the one name by which we are saved and if we honestly care about those we encounter we will seek ways to “do a good deed” that gives glory to the crucified and risen Lord. We love others so that others will love Christ. Bottom line - your mission field is the piece of the planet you inhabit. Time to get busy.