Sayyiduna Abu al-Darda' (may Allah be pleased with him) narrates that the Prophet (peace and blessings be upon him) said: "Shall I not tell you about the greatest of the major sins? Associating partners with Allah, and disobedience to parents." The narrator states: The Prophet (peace and blessings be upon him) was sitting in the manner of ihtiba' (with his knees drawn up and wrapped in his garment). He undid his wrap, took hold of the tip of his tongue and said: "Beware! And false speech (is also among the greatest of the major sins)."
Tabarani recorded it in al-Mu'jam al-Kabir; its chain contains a narrator, Umar bin al-Musawir, and he is munkar al-hadith (his narrations are rejected).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الإيمان / 383