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.