It is narrated from Sayyiduna Abu Bakrah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Shall I not inform you about the greatest of sins?" He said this three times. They said: O Messenger of Allah! Please do tell us. He (peace be upon him) said: "Associating partners with Allah and disobedience to parents." The Prophet (peace be upon him) was reclining, then he sat up straight and said: "Beware! (Also) false speech!" He (peace be upon him) kept repeating this so much that I thought (in my heart): I wish he would stop.

Warrad says that Sayyiduna Muawiyah (may Allah be pleased with him) wrote to Sayyiduna Mughirah bin Shu'bah (may Allah be pleased with him) asking him to write down for him any saying of the Messenger of Allah (peace and blessings be upon him). So he dictated to me, and I wrote with my own hand: I heard the Prophet (peace and blessings be upon him) forbidding excessive questioning, wasting wealth, and idle talk.