Three-fold Reference to Men Blaspheming God:

1. … “And men were scorched with great heat, and blasphemed the name of God, which hath power over these plagues: and they repented not to give him glory.” (Rev. 16:9). (Emphasis added).
2. … “And blasphemed the God of heaven because of their pains and their sores, and repented not of their deeds.”  (Rev. 16:11). (Emphasis added).
3. … ” And there fell upon men a great hail out of heaven, every stone about the weight of a talent: and men blasphemed God because of the plague of the hail; for the plague thereof was exceeding great.” (Rev. 16:21). (Emphasis added).

Commentary: God is blasphemed three (3) times in these verses. From men who are afflicted with three special plagues; noisome sores, scorching heat, heavy hail stones. These men know who is sending them the plagues, and instead of repenting, they curse God. Blaspheme means swearing at, cursing, to speak impiously or irreverently of (God or sacred things). To speak evil of, to slander, to abuse, to speak of or address with irreverence. Men of the earth do not acknowledge God for who he is and instead curse and swear at him, in other words, blaspheme against God.