Qais says that once Hazrat Abu Bakr Siddiq (may Allah be pleased with him) stood up to deliver a sermon, and after praising Allah, he said: O people! You recite this verse: «يَاأَيُّهَاالَّذِينَآمَنُواعَلَيْكُمْأَنفُسَكُمْلَايَضُرُّكُممَّنضَلَّإِذَااهْتَدَيْتُمْإِلَىاللَّـهِمَرْجِعُكُمْجَمِيعًافَيُنَبِّئُكُمبِمَاكُنتُمْتَعْمَلُونَ»[5-المائدة:105] "O you who believe! Take care of your own selves. If you follow the right guidance, no one who goes astray can harm you." But you do not interpret it correctly. I heard the Prophet (peace and blessings of Allah be upon him) say that when people see a sinful act being committed and do not try to change it, soon Allah's punishment will encompass all of them. I also heard Hazrat Abu Bakr Siddiq (may Allah be pleased with him) say: Protect yourselves from lying, for lying is separate from faith.
Hadith Referenceمسند احمد / مسند الخلفاء الراشدين / 16