Ibn Abi Najih (may Allah have mercy on him) said: Tawus (may Allah have mercy on him) was asked about a man who left out one pebble, and he said: He should feed (someone) a morsel. I mentioned this to Mujahid (may Allah have mercy on him), and he said: Abu Abd al-Rahman (Tawus) did not hear the statement of Sayyiduna Sa'd (may Allah be pleased with him). Sayyiduna Sa'd bin Malik (may Allah be pleased with him) said: We returned from the Hajj of the Prophet (peace and blessings be upon him), and some of us would say: I threw six pebbles, and some of us would say: I threw seven pebbles, and none of us found fault with the other for that. [Da'if (weak). Nasa'i: 3077, Ahmad: 1/168; Mujahid (may Allah have mercy on him) did not hear from Sayyiduna Sa'd (may Allah be pleased with him)].
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9669