Tafsir of As-Saffat 37:7

(And as a protection) is in the accusative case as an absolute object (maf‘ul mutlaq) for a verb conjoined to "We have adorned," meaning: "And We have protected it with a protection." Alternatively, it is conjoined to "as an adornment" based on the meaning, for it is in the sense of a causal object (maf‘ul lahu); it is as if it were said: "We created the stars as an adornment for the sky and as a protection for it." Conjunction based on meaning is frequent, and it is distinct from conjunction based on grammatical position (mawdi‘) or conjunction based on presumption (tawahhum). It is also permitted that it be a causal object with the addition of the waw, or by delaying the governing agent, meaning: "And for its protection, We adorned it."

Regarding His saying—the Exalted—: (from every rebellious devil)

(From) relates to the deleted "We have protected" or to "a protection." The marid (rebellious/deviant) is like the murid, stripped of goodness. This is derived from their saying "a bald tree" (shajaran amrad) when it is stripped of its leaves; from this, it is said "a barren sandy stretch" (ramlah marda’) if it grows nothing; and from this comes the word amrad (beardless youth) due to his being stripped of hair. It is interpreted here also as the one who has departed from obedience, which is in the sense of being stripped of it.