Abd al-Rahman bin Abi Bakrah (may Allah have mercy on him) narrates from his father (Sayyiduna Abu Bakrah (may Allah be pleased with him)) that the Messenger of Allah (peace and blessings be upon him) said: "Shall I not tell you of the greatest of the major sins?" He said it three times. They said: Certainly, O Messenger of Allah (peace and blessings be upon him)! He said: "1. Associating partners with Allah, 2. disobedience to parents." The narrator said: He (peace and blessings be upon him) had been reclining, then he sat up and said: "Beware! And false testimony." He (peace and blessings be upon him) kept repeating it, until we said: If only he (peace and blessings be upon him) would fall silent.
(b) In the narration of Ibn Ulayyah: We were sitting with the Prophet (peace and blessings be upon him), and he (peace and blessings be upon him) said: "Shall I not inform you?" and he said: "False testimony," three times.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب آداب القاضي / 20380