"When you meet someone, let you see it is more important than you, And you must say he is better in the sight of Allah than me, and is higher in rank"
If you meet someone who is adulterous, you will-will never know, if he would repent in the future, or even you yourself will fall in it.
But if you’re a spirited Dai Ilallah, you should know that the spirit of propaganda is affection, not the bat, if you want to advise him, Do it with a behavior that forces he believed in you, and from the heart free from hatred.
If you consider only those that get lost, then you yell, insult, berate and beat him, how he would know their error? your dakwah task is how he realized their error, not beat him.