Al-Anbiyaa 21:35

No One has been granted Immortality in this World

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

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

(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.

(then if you die) means, O Muhammad,

(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:

(Everyone is going to taste death,)

(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:

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

(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.

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

What is death?

Allah has said كُلُّ نَفْسٍ ذَائِقَةُ الْمَوْتِ 'Every soul has to taste death'. Here the word soul refers to the living things of the earth, who must all face death, but does not include the angels. There is a difference of opinion about whether the angels will also die or not on the Day of Judgment. Some say that every living thing will die, though momentarily, irrespective of whether they are of the earth or the skies. But others maintain that angels and hurs and ghilman of Paradise are excluded from this general rule. (Only God knows best) (Ruh ul-Ma` ani) Majority of the scholars believe that death is the departure of soul from the mortal human frame, while soul itself is a subtle ethereal living thing which is made of light and resides in human body just as fragrance resides in the rose. Ibn al-Qayyim has convincingly proved this point in his book. (Ruh ul-Ma` ani)

The term ذَائِقَةُ الْمَوْتِ means that every individual will feel the pain of death - 21:35, because considering the manner in which body and soul are conjoined together their separation should obviously entail some pain. There are some saintly persons who regard death as a deliverance from the trials and tribulations of the worldly life and a means of bringing them closer to their Supreme love, that is Allah. This pleasure does not negate the agony of death, because where the reward is high, a little pain is easily tolerated.

Worldly comforts and discomforts are a test

وَنَبْلُوكُم بِالشَّرِّ‌ وَالْخَيْرِ‌ فِتْنَةً

And We test you all through bad and good (situations) with a trial. - 21:35

It means that man is tested both by good things and by bad things. شَر (bad) includes unpleasant things such as illness, grief, pain, poverty etc. while خَیر (good) means desirable things, like good health, happiness, comfort and abundance. Man is subjected to these conditions in this world for test and the test is that he should show patience and endurance in the face of adversity and should offer thanks to Allah when his life is peaceful and comfortable. Wise men have said that, it is more difficult to be steadfast and consistent in offering thanks to Allah for His gifts than to persevere and show patience in difficult circumstances. Sayyidna ` Umar ؓ is reported to have said:

بُلینا بالضّراء فصبرنا و بلینا بالسّراء فلم نصبر (روح المعانی)

"We were tested by discomforts and We bore it with patience, but when we were tested by pleasures, we could not observe patience (i.e. we could not offer gratitude to Allah as was due) ". (Ruh ul-Ma'ani)