كَلَّا سَوْفَ تَعْلَمُونَ ثُمَّ كَلَّا سَوْفَ تَعْلَمُونَ
No indeed—you will soon know; then no indeed—you will soon know. (At-Takathur 102:3–4)
The warning is nearly repeated in full. Its second occurrence intensifies the warning and challenges the audience’s heedlessness. «ثُمَّ» introduces the renewed warning as a further stage.
Contrast: the previous example used repetition to encourage forgiveness; here repetition serves warning. Recognizing the device is not enough without identifying its purpose.