صحيح مسلم

'A'isha reported that when any person fell ill with a disease or he had any ailment or he had any injury, the Messenger of Allah (ﷺ) placed his forefinger upon the ground and then lifted it by reciting the name of Allah. (and said): The dust of our ground with the saliva of any one of us would serve as a means whereby our illness would be cured with the sanction of Allah. This hadith has been transmitted on the authority of Ibn Abu Shaiba and Zubair with a slight variation of wording.