δια-μαρτύρομαι, depon., of Ionic origin, intensive of the simple μαρτύρομαι, which see,
[in LXX chiefly for עוּד hi., usually with dative of person(s), Deu.4:26 8:19, 1Ki.8:9, al. ;]
solemnly to protest: Luk.16:28, Act.2:40 8:25 10:42 18:5 20:21, 23, 24 23:11 28:23, 1Th.4:6, Heb.2:6; in adjuration, before ἐνώπιον τ. θεοῦ, 1Ti.5:21, 2Ti.2:14 4:1 (Cremer, 415).†
(AS)