Mustadrak al-Hakim — Hadith 7677

It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that when the Prophet (peace and blessings be upon him) visited a sick person, he would sit by his head and then recite this supplication seven times: 'As'alullaha al-'Azim, Rabba al-'Arshi al-'Azim, an yashfiyak' (I ask Allah the Mighty, Lord of the Mighty Throne, to heal you). So if his appointed time had not yet come, he would be healed of that illness of his.
This hadith is sahih (authentic) on the condition of the two Shaykhs (Bukhari and Muslim), but they did not record it. No one other than Amr bin al-Harith mentioned Abdullah bin al-Harith between Sa'id and Ibn Abbas, whereas al-Hajjaj bin Artah narrated it from al-Minhal from Abdullah bin al-Harith, and did not mention Sa'id bin Jubayr in between.