His feet like unto fine brass. — The feet, like the feet of the ministering priests of Israel, were bare, and appeared like chalcolibanus (fine brass). The exact meaning of this word (used only here) is not certain. The most trustworthy authors incline to take it as a hybrid word, half Greek, half Hebrew — chalcos, brass, and labân, white, to whiten — and understand it to signify brass which has attained in the furnace a white heat. “Such technical words were likely enough to be current in a population like that of Ephesus, consisting largely of workers in metal, some of whom — if we may judge from the case of Alexander the coppersmith (Acts 19:34; 2 Timothy 4:14) — were, without doubt, Jews. I believe the word in question to have belonged to this technical vocabulary. It is at any rate used by St. John as familiar and intelligible to those for whom he wrote” (Prof. Plumptre in the Epistles to Seven Churches, in loco).
His voice as the sound (better, voice, as the same word — phoné — is used twice, and translated first “voice” and then “sound” in our English version) of many waters. — Daniel described the voice of the Ancient of Days as the voice of a multitude (Daniel 10:6); but the voice of the multitude was in earlier Hebrew writings compared to the sound of the waves of the sea, which the voice of the Lord alone could subdue (Psalms 65:7; Psalms 93:4). This image the Evangelist adopts to describe the voice of Christ — strong and majestic, amid the Babel-sounds of earth. That voice, whose word stilled the sea, sounds as the waves of the sea, which St. John heard Him rebuke.