مَا نُنَزِّلُ الْمَلائِكَةَ إِلاَّ بِالحَقِّ وَمَا كَانُواْ إِذًا مُّنظَرِينَ
[15:8]
We do not send the angels but with truth, and then they would not be respited.
We send not the angels down except for just cause: if they came (to the ungodly), behold! no respite would they have!
We send not down the angels save with the Fact, and in that case (the disbelievers) would not be tolerated.