وَمِنْ شَرِّ حَاسِدٍ إِذَا حَسَدَ
And from the harm of an envier when they envy. (113:5)
Ḥāsid is an indefinite active participle, while ḥasad is a past-tense verb from the same root. With idhā, the expression highlights the circumstance in which the disposition is expressed. The refuge concerns the harm that can proceed from envy; it is not a grammatical declaration that every state of a person has the same effect.
The adjacent participle and verb are not pointless repetition: one identifies a characterizing disposition, the other its operative moment.