Asim bin Damrah (may Allah have mercy on him) said: We asked Sayyiduna Ali (may Allah be pleased with him) about the prayer of the Prophet (peace and blessings be upon him), and Sayyiduna Ali (may Allah be pleased with him) described his (peace and blessings be upon him) prayer, mentioning in it four rak'ahs before Zuhr and two after it, and four rak'ahs before Asr.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4487