ἰσχύω

(ἰσχύς), [in LXX for חָזַק, גִּבּוֹר, עָצַם, etc. ;]

__1. to be strong in body: Mat.9:12, Mrk.2:17.

__2. to be powerful, have power, prevail: Act.19:20, Rev.12:8; before κατά, with genitive of person(s), Act.19:16; with inf. to be able (MM, Exp. xv): Mat.8:28 26:40, Mrk.5:4 9:18 (inf. understood) Mrk.14:37, Luk.6:48 8:43 13:24 14:6, 29-30 16:3 20:26, Jhn.21:6, Act.6:10 15:10 25:7 27:16; with accusative, Php.4:13, Jas.5:16; of things, to avail, be serviceable (MM, Exp. l.with): Mat.5:13, Gal.5:6, Heb.9:17 (cf. ἐν-, ἐξ-, ἐπ-, κατ-ισχύω).†

(AS)

to be strong; to be powerful; have power; prevail; to be able; to avail; be serviceable