Al-Anbya 21:39

Law yaAAlamu allatheena kafaroo heenala yakuffoona AAan wujoohihimu annara walaAAan thuhoorihim wala hum yunsaroon

If those who disbelieved but knew the time when they will not avert the Fire from their faces or from their backs and they will not be aided...

Only if the disbelievers were to know the time when they will not (be able to) keep off the fire from their faces or from their backs, nor will they be helped.