A.T. Robertson Commentary James 5:17

"Elijah was a man of like passions with us, and he prayed fervently that it might not rain; and it rained not on the earth for three years and six months." — James 5:17 (ASV)

Of like passions with us (ομοιοπαθης ημιν). Associative-instrumental case ημιν as with ομοιος. This old compound adjective (ομοιοσ, πασχω), suffering the like with another, in N.T. only here and Ac 14:15.

He prayed fervently (προσευχη προσηυξατο). First aorist middle indicative of προσευχομα and the instrumental case προσευχη (cognate substantive), after idiom for intensity in classical Greek, like φευγειν φυγη, to flee with all speed (figura etymologica), but particularly frequent in the LXX (Genesis 2:17; Genesis 31:30) in imitation of the Hebrew infinitive absolute. So Lu 22:15; John 3:29; Acts 4:17.

That it might not rain (του μη βρεξα). Genitive of the articular infinitive (βρεξα, first aorist active of βρεχω, old verb, to moisten, Luke 7:38, to rain, Matthew 5:45) with negative μη used either for direct purpose, for an object clause as here and Ac 3:12; 15:20, or even for result.

For three years and six months (ενιαυτους τρεις κα μηνας εξ). Accusative of extent of time.