مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2177
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه) that the Prophet (ﷺ) said: "No one visits a sick person whose time [of death] has not yet come and says seven times, 'I ask Allah the Almighty, Lord of the Mighty Throne, to heal him, but he will be healed."
Musnad Ahmad 2182A saheeh hadeeth]