Allah says:

[وَمَا جَعَلْنَا لِبَشَرٍ مِّن قَبْلِكَ]

(And We granted not to any human being immortality before you;) means, O Muhammad.

[الْخُلْدَ]

(immortality) means, in this world. On the contrary,

[كُلُّ مَنْ عَلَيْهَا فَانٍ - وَيَبْقَى وَجْهُ رَبِّكَ ذُو الْجَلْـلِ وَالإِكْرَامِ ]

(Whatsoever is on it (the earth) will perish. And the Face of your Lord full of majesty and honor will remain forever.) [55:26-27].

[أَفَإِيْن مِّتَّ]

(then if you die) means, O Muhammad,

[فَهُمُ الْخَـلِدُونَ]

(would they live forever) means, they hope that they will live forever after you, but that will not happen; everything will pass away. So Allah says:

[كُلُّ نَفْسٍ ذَآئِقَةُ الْمَوْتِ]

(Everyone is going to taste death,)

[وَنَبْلُوكُم بِالشَّرِّ وَالْخَيْرِ فِتْنَةً]

(and We shall test you with evil and with good by way of trial. ) Meaning, "We shall test you, sometimes with difficulties and sometimes with ease, to see who will give thanks and who will be ungrateful, who will have patience and who will despair.'' `Ali bin Abi Talhah reported from Ibn `Abbas:

[وَنَبْلُوكُم]

(and We shall test you) means, We will test you,

[بِالشَّرِّ وَالْخَيْرِ فِتْنَةً]

(with evil and with good by way of trial.) means, with difficulties and with times of prosperity, with health and sickness, with richness and poverty, with lawful and unlawful, obedience and sin, with guidance and misguidance.

[وَإِلَيْنَا تُرْجَعُونَ]

(And to Us you will be returned.) means, and We will requite you according to your deeds.

[وَإِذَا رَآكَ الَّذِينَ كَفَرُواْ إِن يَتَّخِذُونَكَ إِلاَّ هُزُواً أَهَـذَا الَّذِى يَذْكُرُ آلِهَتَكُمْ وَهُمْ بِذِكْرِ الرَّحْمَـنِ هُمْ كَـفِرُونَ - خُلِقَ الإنْسَانُ مِنْ عَجَلٍ سَأُوْرِيكُمْ ءَايَـتِى فَلاَ تَسْتَعْجِلُونِ ]

(36. And when those who disbelieved see you, they take you not except for mockery (saying): "Is this the one who talks about your gods'' While they disbelieve at the mention of the Most Gracious.) (37. Man is created of haste. I will show you My Ayat. So ask Me not to hasten (them).)