Is there any authentic Hadith which says there is shifa (cure) in the left over food and drink of a Muslim?
This is understood from a hadith in Sahih Bukhari (Hadith: 5746) and Sahih Muslim (Hadith: 5683) in which Rasulullah (sallallahu’alayhi wasallam) is reported to have recited the following du’a for the sick:
“Bismillahi turbatu ardina bi riqati ba’dina li yushfa saqimuna bi idhni Rabbina”
Translation: In the name of Allah, (we take) the soil of our land, with our saliva so that our sick are cured
In this narration, Rasulullah (sallallahu’alayhi wasallam) used saliva for the purpose of shifa (cure). The left over food of a person is generally mixed with his/her saliva.
The Muhaddithun have mentioned that this applies to anybody’s saliva, even though the saliva of our Master (sallallahu’alayhi wasallam) has much more blessing.
References for the above
Fathul Bari, Hadith; 5746, Sharhun Nawawi ‘ala Sahih Muslim, Hadith: 5683, Al-Ubby, Hadith: 2194, and Al-Maqasidul Hasanah, Hadith: 534.
Some people quote the following words as a Hadith:
The saliva/ leftover of a believer is shifa (cure)
These words cannot be traced as an explicit hadith and should therefore not be quoted as such.
(Al-Masnu’, Hadith: 144 and 150)
However, as explained above, the meaning is indeed correct and is derived from an authentic Hadith. (Al-Maqasidul Hasanah, Hadith: 534 and Al Yawaqitul Ghaliyah, vol.2 pg.127)
And Allah Ta’ala Knows best.