The One Wrapping Himself Up - 74:31
"We have appointed only angels as guardians of the Fire, and We have made their number (nineteen) a trial for the disbelievers, to convince those who have been given the Book, to strengthen the faith of those who believe, to remove the doubts of those who have been given the Book and those who believe, and for those in whose hearts is a disease and the disbelievers to say, "What does Allah mean by this example?"So Allah leads astray whom He wills and guides whom He wills. None knows the armies of your Lord except Himself. This (number) is a message to the people."
Related:
The Night Journey/17:59
The fact that those before denied them did not prevent Us from sending signs. For example, We had clearly given the camel to Thamud. But they wronged him. We send the signs only as a warning.
The Moon/54:1
The Hour (the end of the world) is near and the moon has split.
The Moon/54:2
"If they see a miracle, they turn away and say, "It is a continuing magic"."
The Moon/54:3
They denied and followed their desires and the status quo.
The Moon/54:4
But the news has come to them, full of warnings to prevent their evil deeds.
The Moon/54:5
This is a superior wisdom, but the warnings do not avail.
The Arabic Letter Sad/38:1
By this Qur´an, which contains the message.