Muharrar bin Abi Hurayrah (may Allah have mercy on him) narrates from his father (may Allah be pleased with him) that he said: I was with Sayyiduna Ali (may Allah be pleased with him) when the Prophet (peace and blessings be upon him) sent him with (the declaration of) Bara'ah to the people of Makkah. He (Sayyiduna Abu Hurayrah) says: I kept announcing until my voice became hoarse. He was asked: "What were you announcing?" He said: "We were ordered to announce these matters: (1) None will enter Paradise except a believer. (2) Whoever had a covenant with the Prophet (peace and blessings be upon him), its term is four months. (3) When the four months have passed, Allah and His Messenger (peace and blessings be upon him) are free (of the polytheists). (4) The House of Allah shall not be circumambulated naked. (5) After this year no polytheist shall perform Hajj."
(b) Zayd bin Yuthay' (may Allah have mercy on him) narrates from Sayyiduna Ali (may Allah be pleased with him) that whoever had a treaty, it will be fulfilled, and whoever had no treaty, his term is four months.
Imam al-Shafi'i (may Allah have mercy on him) says: "The Messenger of Allah (peace and blessings be upon him) gave Safwan bin Umayyah a respite of four months after the conquest of Makkah."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الجزية / 18821