Sila bin Zufar narrates: We were present with Sayyiduna Ammar bin Yasir (may Allah be pleased with him) on a day about which there was doubt as to whether it was Ramadan or not. A goat was brought, so a person withdrew. Sayyiduna Ammar bin Yasir (may Allah be pleased with him) said: Whoever fasts on this day has disobeyed Sayyiduna Abu al-Qasim (peace and blessings be upon him).