It is narrated from Sayyiduna Abdullah bin Sa’ib (may Allah be pleased with him) that when the Prophet (peace and blessings of Allah be upon him) began the Fajr prayer on the day of the conquest of Makkah, he recited Surah Al-Mu’minun in it. But when he reached the mention of Sayyiduna Musa and Harun, he began to cough, so he shortened the recitation and went into bowing (ruku’).