﴿ وَمَا جَعَلْنَا لِبَشَرٍۢ مِّن قَبْلِكَ ٱلْخُلْدَ ۖ أَفَإِي۟ن مِّتَّ فَهُمُ ٱلْخَٰلِدُونَ ﴾

“AND [remind those who deny thee, O Prophet, that] never have We granted life everlasting to any mortal before thee: but do they, perchance, hope that al­though thou must die, they will live forever?””

When the disbelievers said that Muhammad (s) would die the following was revealed And We did not assign to any human being before you immortality permanence of life in this world. What if you are fated to die will they be immortal? in it? No! The last sentence constitutes the syntactical locus of the interrogative of denial.