Gird thy sword upon thy thigh, O most mighty, with thy glory and thy majesty.
Gird thy sword upon thy thigh, O (Most) Mighty - in order that thou mayest, by destroying thine enemies (cf. the type, 1 Samuel 25:13), take the kingdom to thyself which is thine own (cf. Revelation 11:15; Revelation 11:17). The last event before "the marriage of the Lamb" is, He that is "Faithful and True ... in righteousness doth judge and make war: and out of His mouth goeth a sharp sword, that with it He should smite the nations; and He hath on His vesture ... a name written, KING OF KINGS AND LORD OF LORDS" (cf. Revelation 19:7; Revelation 19:11-21; Revelation 20:4-6; Revelation 21:8-9).
With thy glory and thy majesty - in apposition to '(Gird thyself) with thy sword (upon thy thigh).' His destroying sword is the instrument wherewith His glory and His majesty vindicate and manifest themselves. Compare Psalms 21:5; and the type, Solomon, 1 Chronicles 29:25. The imperative "gird" is God's inspired Word-sure to bring to pass that which it commands. The future naturally follows - "thy right hand shall teach thee terrible things" (Psalms 45:4). His 'glory and majesty' answers to His Godhead; His might as a Hero (which the Hebrew, gibbor, "O Most Mighty," may be rendered) answers to His causing 'the people to fall under Him' (Psalms 45:5). Compare Psalms 110:5. The two are combined in Isaiah 9:6, where He is called "the mighty (or hero) God."