Rev 16:8 And the fourth angel poured out his vial upon the sun; and power was given unto him to scorch men with fire.
Rev 16:9 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.
Alas, this could even be you or I blaspheming, if we harden our hearts.