Abbas - Tanwîr al-Miqbâs min Tafsîr Ibn ‘Abbâs
(Those who were left behind rejoiced) the hypocrites were pleased (at sitting still) at staying behind and not joining the battle of Tabuk (behind the Messenger of Allah, and were averse to striving with their wealth and their lives in Allah's way) in obedience of Allah. (And they said) to one another: (Go not forth in the heat!) do not go with Muhammad (pbuh) to the battle of Tabuk in the scorching heat. (Say) to them, O Muhammad: (The heat of hell is more intense of heat) is most intense in firebrands, (if they but understood) and believed.
Those who were left behind, from [the journey to] Tabūk, rejoiced at remaining behind the Messenger of God, and were averse to striving with their wealth and their lives in the way of God. And they said, that is, they said to one another, ‘Do not go forth, do not set off to [join] the fight, in the heat!’ Say: ‘The fire of Hell is hotter, than Tabūk, and more worthy for them to guard against, by not staying behind, did they but understand’, this, they would not have stayed behind.
Hypocrites rejoice because They remained behind from Tabuk!
Allah admonishes the hypocrites who lagged behind from the battle of Tabuk with the Companions of the Messenger of Allah, rejoicing that they remained behind after the Messenger departed for the battle,
وَكَرِهُواْ أَن يُجَـهِدُواْ
(they hated to strive and fight), along with the Messenger,
(with their properties and their lives in the cause of Allah, and they said), to each other,
لاَ تَنفِرُواْ فِى الْحَرِّ
("March not forth in the heat.'') Tabuk occurred at a time when the heat was intense and the fruits and shades became delightful. This is why they said,
لاَ تَنفِرُواْ فِى الْحَرِّ
("March not forth in the heat'') Allah said to His Messenger,
(Say) to them,
("The fire of Hell...), which will be your destination because of your disobedience,
("...is more intense in heat;''), than the heat that you sought to avoid; it is even more intense than fire. Imam Malik narrated that Abu Az-Zinad said that Al-A`raj narrated that Abu Hurayrah said that the Messenger of Allah said,
(On the Day of Resurrection, the person who will receive the least punishment among the people of the Fire, wears two slippers made from the Fire of Jahannam causing his brain to boil, just as a pot boils. He thinks that none in the Fire is receiving a more severe torment than he, when in fact he is receiving the least torment.) The Two Sahihs collected this Hadith. There are many other Ayat and Prophetic Hadiths on this subject. Allah said in His Glorious Book,
كَلاَّ إِنَّهَا لَظَى - نَزَّاعَةً لِّلشَّوَى
(By no means! Verily, it will be the Fire of Hell. Taking away (burning completely) the scalp!) 70:15-16,
(Al-Hamim (boiling water) will be poured down over their heads. With it will melt (or vanish away) what is within their bellies, as well as (their) skins. And for them are hooked rods of iron (to punish them). Every time they seek to get away therefrom, from anguish, they will be driven back therein, and (it will be said to them): "Taste the torment of burning!'') 22:19-22, and,
(Surely, those who disbelieved in Our Ayat, We shall burn them in Fire. As often as their skins are roasted through, We shall change them for other skins that they may taste the punishment.)4:56 Allah said here,
(Say: "The fire of Hell is more intense in heat;'' if only they could understand!) meaning, if they have any comprehension or understanding, they would have marched with the Messenger of Allah during the heat, so as to save themselves from the Fire of Jahannam, which is much more severe. Allah, the Exalted, then warns the hypocrites against their conduct,
(So let them laugh a little...) Ibn Abi Talhah reported that Ibn `Abbas commented, "Life is short, so let them laugh as much as they like in it. But when life ends and they are returned to Allah, the Exalted and Most Honored, they will start crying forever without end.''