What rhetorical condition explains the reinforcement in “إِنَّهُمْ مُغْرَقُونَ”?

ʿIlm al-Maʿānī: Predication, Emphasis, and Rational Metaphor

• Always silencing a denier
• Turning a statement into a command
• Treating a non-questioner as expectant of an answer
• Making the subject unknown