مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2134
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas (رضي الله عنه) - Abu Mu'awiyah said: I think he attributed it to the Prophet (ﷺ) - said: “Whoever visits a sick person and says, “I ask Allah the Almighty, Lord of the Mighty Throne, to heal you,' seven times, Allah will heal him if his time [of death] is delayed.”
Musnad Ahmad 2138A saheeh hadeeth]