Hadith: O Allah, Lord of mankind, remove the affliction, and cure; for You are the one who cures

عن عائشة رضي الله عنها مرفوعاً: أن النبيَّ صلى الله عليه وسلم كَانَ يَعُودُ بَعْضَ أهْلِهِ يَمْسَحُ بِيدِهِ اليُمْنَى، ويقول: «اللَّهُمَّ رَبَّ النَّاسِ، أذْهِب البَأسَ، اشْفِ أنْتَ الشَّافِي لاَ شِفَاءَ إِلاَّ شِفاؤكَ، شِفَاءً لاَ يُغَادِرُ سَقماً».
[صحيح] - [متفق عليه]

‘Ā'ishah (may Allah be pleased with her) reported that when the Prophet (may Allah's peace and blessings be upon him) visited some of his family members who were sick, he would pass his right hand over them and say: "O Allah, Lord of mankind, remove the affliction. Cure, for You are the one who cures; there is no cure but Yours, a cure that leaves behind no trace of sickness."
Sahih/Authentic. - [Al-Bukhari and Muslim]

Explanation

The Prophet (may Allah's peace and blessings be upon him) used to visit some of his wives who were ill, he would supplicate for them with this supplication, and would pass his right hand over them and read this supplication: "O Allah, Lord of mankind," imploring Allah by His universal Lordship, for He is the Lord, the Creator, the Owner, and the Regulator of all affairs. "Remove the affliction," meaning the sickness that affected this person. Cure means remove the sickness and heal the sick. Ash-Shāfi (The Curer or the Healer) is one of Allah's beautiful names, because He is the one who cures the sick. "No one can cure except You," i.e. there is no cure except Allah's cure. Recovering at the hands of human beings is only a means, but the one who cures is Allah. The Prophet asked Allah to cure the sick person completely whereby no trace of illness remains.