Message of Abu Bakr siddiq (RA)

Bismillah hirrahmaani raheem ...
(5:105) Believers! Take heed of your own selves. If you are rightly guided, the error of he who strays will not harm you*To Allah will all of you return; then He will let all of you know what you did.
*. What is stressed here is that rather than occupying himself unduly with examining faults in the belief and conduct of others, a man should pay greater attention to a critical examination of his own conduct. His primary concern should be with his own faith and conduct. If a man is himself obedient to God, observes his duties to Him and to His creatures including his duty to promote what is good and forbid what is evil, and lives according to the dictates of righteousness and honesty, he has fulfilled his obligation and if others persist either in false beliefs or in moral corruption their errors cannot harm him. This verse in no way means that a man should care only for his own salvation and should remain unconcerned with the reform of others.
Abu Bakr removed this misconception in one of his sermons when he remarked: 'You recite this verse but interpret it erroneously. I have heard the Messenger of Allah (peace be on him) say that when people see corruption but do not try to change it; and when they see a wrong-doer commit wrong but do not prevent him from doing so, it is not unlikely that God's chastisement will seize them all(both good and bad believers). By God, it is incumbent upon you that you bid what is good and forbid what is evil or else God will grant domination upon you to those who are the worst among you. They will greatly chastise you and then when your righteous ones pray to God, their prayers will not be answered.'