Tafsir of Sad 38:42

"Strike with your foot" is either a narration of what was said to him, or it is the content of a suppressed imperative connected to the preceding "He called out," meaning: "So We said to him, 'Strike with your foot,'" that is, strike the ground with it.

Likewise, the saying of the Exalted, "This is a cool [spring] to wash with and a drink," is either a narration of what was said to him after he complied with the command and the water gushed forth, or it is the content of a suppressed imperative connected to a suppressed clause that the discourse implies, as if it were said: "So he struck it, and a spring gushed forth, and We said to him, 'This is a wash to cleanse yourself with, and a drink to consume, so that your outward and inward [ailments] may be healed.'"

Mughtasal (a place/means to wash) is a noun of patient (passive participle) used with the omission of the preposition (and attachment of the verb to the noun). The same applies to sharāb (a drink). It is narrated from Muqatil that mughtasal is a noun of place—meaning "this is a place in which you wash"—but this is not well-founded, and the apparent meaning of the verse suggests that one source is described as both a wash and a drink.

It is said that he, upon him be peace, struck with his right foot and a hot spring gushed forth, from which he washed, and he struck with his left foot and a cold spring gushed forth, from which he drank. Al-Hasan said: He struck with his foot and a spring gushed forth, from which he washed; then he walked about forty cubits and struck with his foot, and another [spring] gushed forth, from which he drank. Perhaps by the first, he meant a hot spring. However, the apparent structure of the discourse does not indicate plurality.

Bārid (cool) in that context is an adjective for sharāb (drink), even though it precedes it as an adjective for mughtasal (wash). To suggest that "this" refers to the nature of what gushed forth, or to assume "and this is cool, etc.," is an affectation that does not escape weakness.

It is said that the command to strike with the foot was so that every ailment might be scattered from his body.

This occurred, according to what is narrated from Qatadah, Al-Hasan, and Muqatil, in the land of Al-Jabiya in the Levant. There is also an ellipsis in the discourse, meaning: "So he washed and drank, and through that, We removed the affliction that had befallen him."