(Swaad) 38 : 42
ارْكُضْ بِرِجْلِكَ ۖ هَٰذَا مُغْتَسَلٌ بَارِدٌ وَشَرَابٌ
You strike with your leg, this is a cool spring for baths and drinks.
Allah who accepted the prayer of Ayyoob commanded him to strike with his leg on the earth and thereby gushed out a spring of cold water for drinking and bathing. Thus the illness of Prophet Ayyoob was recovered and he got back his health. See explanation 26: 80 and 36: 82-83.