Here, Allah mentions the punishment of the disbelievers and the reward of the righteous believers, after describing the Kufr and Shirk that the disbelievers indulge in,
{For them is a torment in the life of this world,}

by the hands of the believers, killing and capturing them,
{and certainly, the torment of the Hereafter.} which will come after they suffer humiliation in this life,
{is harder} many times harder. The Messenger of Allah said to those who agreed to Mula'anah
"Surely, the torment of this life, is easier than the torment of the Hereafter."
Indeed, and just as the Messenger of Allah stated, the torment of this life ends but the torment of the Hereafter is everlasting in a Fire that is seventy times hot than our fire, where there are chains whose thickness and hardness are unimaginable. Allah said in other Ayat,
{So on that Day none will punish as He will punish. And none will bind as He will bind.} [89:25-26], and,
{And for those who deny the Hour, We have prepared a flaming Fire. When it (Hell) sees them from a far place, they will hear its raging and its roaring. And when they shall be thrown into a narrow place thereof, chained together, they will exclaim therein for destruction. Exclaim not today for one destruction, but exclaim for many destructions. Say: "Is that (torment) better, or the Paradise of Eternity promised for those who have Taqwa?" It will be theirs as a reward and as a final destination.} [25:11-15]
Similarly He said;
{The description of the Paradise which those who have Taqwa have been promised}

meaning its description and qualities;
{Underneath it rivers flow}

these rivers flow in the various parts and grades of Paradise and wherever its people wish they flow and gush forth for them.
Allah also said,
{The description of Paradise which those who have Taqwa have been promised (is that) in it are rivers of water the taste and smell of which are not changed, rivers of wine delicious to those who drink, and rivers of clarified honey, therein for them is every kind of fruit, and forgiveness.} [47:15]
Allah said next,
{its provision is eternal and so is its shade}

meaning, it has foods, fruits and drinks that never end. An authentic Hadith states,
"While in my place here, I saw Paradise and reached for a bunch (of fruit). Had I taken it, you would have continued eating from it as long as this life remains."
The Prophet also said,
"The people of Paradise eat and drink, but they do not blow their noses, defecate or urinate. Their food digestion turns into a burp, like the scent of musk. They are inspired to glorify and praise (Allah) as you are inspired to breathe."
They asked, 'O Allah's Messenger! What happens to the call of nature, but Paradise is pure [from feces and urine]?' The Prophet said,
'One of them (residents of Paradise) relieves the call of nature through a sweat that emanates from the skin, with the scent of musk, and the stomach becomes empty again.'
Imam Ahmad and An-Nasa'i collected this Hadith.
Allah said in other Ayat,
{And fruit in plenty, whose supply is not cut off nor are they out of reach.} [56:32-33], and,
{And the shade thereof is close upon them, and the bunches of fruit thereof will hang low within their reach.} [76:14]
The shade of Paradise is everlasting and never shrinks, just as Allah said,
{But those who believe and do deeds of righteousness, We shall admit them to Gardens under which rivers flow, abiding therein forever. Therein they shall have pure mates, and We shall admit them to shades wide and ever deepening.} [4:57]
Allah often mentions the description of Paradise and the description of the Fire together, to make Paradise appealing and warn against the Fire. This is why, after Allah mentioned the description of Paradise here. He next said,
{this is the end (final destination) of those who have Taqwa, and the end (final destination) of the disbelievers is Fire.}

Allah said in another Ayah,
{Not equal are the dwellers of the Fire and the dwellers of the Paradise. It is the dwellers of Paradise that will be successful.} [59:20]