Allah tells us that not everyone who desires this world and its luxuries gets what he wants. That is attained by those whom Allah wants to have it, and they get what He wills that they should get. This Ayah narrows down the general statements made in other Ayat. Allah says:

﴿عَجَّلْنَا لَهُ فِيهَا مَا نَشَآءُ لِمَن نُّرِيدُ ثُمَّ جَعَلْنَا لَهُ جَهَنَّمَ﴾

(We readily grant him what We will for whom We like. Then, afterwards, We have appointed for him Hell) meaning, in the Hereafter,

﴿يَصْلَـهَآ﴾

(he will burn therein) means, he will enter it until it covers him on all sides,

﴿مَذْمُومًا﴾

(disgraced) means, blamed for his bad behaviour and evil deeds, because he chose the transient over the eternal,

﴿مَّدْحُورًا﴾

(rejected.) means, far away (from Allah's mercy), humiliated and put to shame.

﴿وَمَنْ أَرَادَ الاٌّخِرَةَ﴾

(And whoever desires the Hereafter) wanting the Hereafter and its blessings and delights,

﴿وَسَعَى لَهَا سَعْيَهَا﴾

(and strives for it, with the necessary effort due for it) seeking it in the right way, which is following the Messenger .

﴿وَهُوَ مُؤْمِنٌ﴾

(while he is a believer,) means, his heart has faith, i.e., he believes in the reward and punishment,

﴿فَأُولَـئِكَ كَانَ سَعْيُهُم مَّشْكُورًا﴾

(then such are the ones whose striving shall be appreciated, (rewarded by Allah).)

﴿كُلاًّ نُّمِدُّ هَـؤُلاءِ وَهَـؤُلاءِ مِنْ عَطَآءِ رَبِّكَ وَمَا كَانَ عَطَآءُ رَبِّكَ مَحْظُورًا - انظُرْ كَيْفَ فَضَّلْنَا بَعْضَهُمْ عَلَى بَعْضٍ وَلَلاٌّخِرَةُ أَكْبَرُ دَرَجَـتٍ وَأَكْبَرُ تَفْضِيلاً ﴾

(20. On each these as well as those We bestow from the bounties of your Lord. And the bounties of your Lord can never be forbidden.) (21. See how We prefer one above another (in this world), and verily, the Hereafter will be greater in degrees and greater in preferment.) Allah says:

﴿كَلاَّ﴾

On each meaning, on each of the two groups, those who desire this world and those who desire the Hereafter, We bestow what they want

﴿مِنْ عَطَآءِ رَبِّكَ﴾

(from the bounties of your Lord.) means, He is the One Who is in control of all things, and He is never unjust. He gives to each what he deserves, whether it is eternal happiness or doom. His decree is unstoppable, no one can withhold what He gives or change what He wants. Allah says:

﴿وَمَا كَانَ عَطَآءُ رَبِّكَ مَحْظُورًا﴾

(And the bounties of your Lord can never be forbidden.) meaning, no one can withhold or prevent them. Qatadah said,

﴿وَمَا كَانَ عَطَآءُ رَبِّكَ مَحْظُورًا﴾

(And the bounties of your Lord can never be forbidden.) "(It means) they can never decrease''.

﴿وَمَا كَانَ عَطَآءُ رَبِّكَ مَحْظُورًا﴾

(And the Bounties of your Lord can never be forbidden) Al-Hasan and others said, "(It means) they can never be prevented.'' Then Allah says:

﴿انظُرْ كَيْفَ فَضَّلْنَا بَعْضَهُمْ عَلَى بَعْضٍ﴾

(See how We prefer one above another,) meaning in this world, so that some are rich and some are poor, and others are in between; some are beautiful, some are ugly and others are in between; some die young while others live to a great age, and some die in between.

﴿وَلَلاٌّخِرَةُ أَكْبَرُ دَرَجَـتٍ وَأَكْبَرُ تَفْضِيلاً﴾

(and verily, the Hereafter will be greater in degrees and greater in preferment.) means, the differences between them in the Hereafter will be greater than the differences between them in this world. Some of them will be in varying levels of Hell, in chains and fetters, while others will be in the lofty degrees of Paradise, with its blessings and delights. The people of Hell will vary in their positions and levels, just as the people of Paradise will. In Paradise there are one hundred levels, and the distance between one level and another is like the distance between heaven and earth. It is recorded in the Two Sahihs that the Prophet said:

«إِنَّ أَهْلَ الدَّرَجَاتِ الْعُلَى لَيَرَوْنَ أَهْلَ عِلِّيِّينَ كَمَا تَرَوْنَ الْكَوْكَبَ الْغَابِرَ فِي أُفُقِ السَّمَاء»

(The people of the highest levels (of Paradise) will see the people of `Illiyin as if they are looking at distant stars on the horizon.) Allah says:

﴿وَلَلاٌّخِرَةُ أَكْبَرُ دَرَجَـتٍ وَأَكْبَرُ تَفْضِيلاً﴾

(and verily, the Hereafter will be greater in degrees and greater in preferment.)

﴿لاَّ تَجْعَل مَعَ اللَّهِ إِلَـهًا ءَاخَرَ فَتَقْعُدَ مَذْمُومًا مَّخْذُولاً ﴾

(22. Set not up with Allah any other ilah (god), or you will sit down reproved, forsaken (in the Hellfire).)