Al-Muddaththir 74:31

And We have appointed only angels as wardens of the Fire, in other words, and so they cannot be withstood as these [disbelievers are wont to] imagine; and We have made their number, so, only as a stumbling-block, a cause for error, for those who disbelieve, when they then say, ‘Why are there nineteen of them?’, so that those who were given the Scripture, namely, the Jews, may be certain, of the sincerity of the Prophet (s) in [saying that] they are nineteen, for this concords with what is in their Scripture; and that those who believe, from among the People of the Scripture, may increase in faith, in affirmation of the truth, given that what the Prophet (s) has said concords with what is in their Scripture, and that those given the Scripture and the believers, [those] other than these [Jews], may not be in doubt, concerning the number of [these] angels, and that those in whose hearts there is a sickness, an uncertainty, [those] in Medina, and the disbelievers, in Mecca, may say, ‘What did God mean by this, number [as a], similitude?’ (mathalan: they referred to it thus [as a mathal] on account of it being a curious matter; in terms of syntax, it [mathalan] is a circumstantial qualifier). Thus, that is, just as the one who rejects this number is led astray and the one who affirms the truth of it is guided, God leads astray whom He will and guides whom He will. And none knows the hosts of your Lord, namely, the angels, [none knows them] in terms of their strength and their assistants, except Him. And it, that is, Saqar, is nothing but a reminder for humans.