The messenger (an angel, as clarified in v. 17) declares his authority—being sent from Yahweh—and also reminds Alma2 of the proof of his power: first, that Alma2 can visually see him, and second, that his voice shook the earth. (See commentary accompanying vv. 10–11.) The angel explicitly cites these two elements as proof of divine origin. The angel does not mention a cloud but the description does (v. 11). Thus, the angel explicitly reminds Alma2 of three indubitable markers of divinity: the cloud, the voice as thunder, and the shaking of the earth. The angel’s repetition should confirm that these markers are significant, not simply descriptive.