‘Ali ibn Abi Tālib (may Allah be pleased with him) reported: I never had sore eyes nor a headache since the Messenger of Allah (may Allah's peace and blessings be upon him) wiped my face and spat in my eyes on the Day of Khaybar when he gave me the standard.
During the battle of Khaybar, ‘Ali ibn Abi Tālib (may Allah be pleased with him) had sore eyes. So, the Prophet (may Allah's peace and blessings be upon him) summoned him. He wiped his face and spat into his eyes so his eyes recovered by Allah's permission. The Prophet (may Allah's peace and blessings be upon him) then gave him the standard, and Allah granted Muslims victory in conquering the fortress of Khaybar at the hands of ‘Ali. ‘Ali (may Allah be pleased with him) says that he never had sore eyes nor a headache after the Prophet (may Allah's peace and blessings be upon him) had wiped his face and spat in his eyes during the battle of Khaybar. This is an evident miracle of the Prophet (may Allah's peace and blessings be upon him).