‘A’ishah said : When a man complained of pain the Prophet (ﷺ) said to him pointing to his saliva and mixing it with dust :(This is) the dust of our earth, mixed with saliva of us, so that our sick is remedied with the permission of our lord
SahihSahihSahih Bukhari (5745) Sahih Muslim (2194)Book 29 · Hadith 41