Since Allah mentioned the condition of the people of Hell, He followed that by mentioning the people of Paradise. He tells us that they will dwell in Gardens and water springs.
ادْخُلُوهَا بِسَلَـمٍ
(Enter it in peace) meaning free of all problems.
ءَامِنِينَ
(and security.) meaning free from all fear and concern. They will not have any fear of expulsion, nor will they fear that their condition will be disrupted or end.
وَنَزَعْنَا مَا فِى صُدُورِهِم مِّنْ غِلٍّ إِخْوَانًا عَلَى سُرُرٍ مُّتَقَـبِلِينَ
(And We shall remove any deep feeling of bitterness from their breasts. (So they will be like) brothers facing each other on thrones.) Al-Qasim narrated that Abu Umamah said: "The people of Paradise will enter Paradise with whatever enmity is left in their hearts from this world. Then, when they come together, Allah will remove whatever hatred the world has left in their hearts." Then he recited:
وَنَزَعْنَا مَا فِى صُدُورِهِم مِّنْ غِلٍّ
(And We shall remove any deep feeling of bitterness from their breasts.) This is how it was narrated in this report, but Al-Qasim bin `Abdur-Rahman is weak in his reports from Abu Umamah. However, this is in accord with the report in the Sahih where Qatadah says, "Abu Al-Mutawakkil An-Naji told us that Abu Sa`id Al-Khudri told them that the Messenger of Allah ﷺ said:
«يَخْلُصُ الْمُؤْمِنُونَ مِنَ النَّارِ، فَيُحْبَسُونَ عَلَى قَنْطَرَةٍ بَيْنَ الْجَنَّةِ وَالنَّارِ. فَيُقْتَصُّ لِبَعْضِهِمْ مِنْ بَعْضٍ مَظَالِمُ كَانَتْ بَيْنَهُمْ فِي الدُّنْيَا حَتَّى إِذَا هُذِّبُوا وَنُقُّوا، أُذِنَ لَهُمْ فِي دُخُولِ الْجَنَّة»
(The believers will be removed from the Fire, and they will be detained on a bridge between Paradise and Hell. Then judgment will be passed between them concerning any wrong they have committed in this world against one another, until they are cleansed and purified. Then permission will be given to them to enter Paradise.)"
لاَ يَمَسُّهُمْ فِيهَا نَصَبٌ
(No sense of fatigue shall touch them) meaning no harm or hardship, as was reported in the Sahihs:
«أَنَّ اللهَ أَمَرَنِي أَنْ أُبَشِّرَ خَدِيجَةَ بِبَيْتٍ فِي الْجَنَّةِ مِنْ قَصَبٍ لَا صَخَبَ فِيهِ وَلَا نَصَب»
(Allah commanded me to tell Khadijah the good news of a jeweled palace in Paradise in which there will be no toil and no fatigue.)
وَمَا هُمْ مِّنْهَا بِمُخْرَجِينَ
(nor shall they (ever) be asked to leave it.) As was reported in the Hadith:
«يُقَالُ: يَا أَهْلَ الْجَنَّةِ إِنَّ لَكُمْ أَنْ تَصِحُّوا فَلَا تَمْرَضُوا أَبَدًا، وَإِنَّ لَكُمْ أَنْ تَعِيشُوا فَلَا تَمُوتُوا أَبَدًا،وَإِنَّ لَكُمْ أَنْ تَشِبُّوا فَلَا تَهْرَمُوا أَبَدًا، وَإِنَّ لَكُمْ أَنْ تُقِيمُوا فَلَا تَظْعُنُوا أَبَدًا»
(It will be said, O dwellers of Paradise! You will be healthy and never fall sick; you will live and never die; you will be young and never grow old; you will stay here and never leave.) Allah says:
خَـلِدِينَ فِيهَا لاَ يَبْغُونَ عَنْهَا حِوَلاً
(Wherein they shall dwell (forever). They will have no desire to be removed from it.) (18:108)
نَبِّىءْ عِبَادِى أَنِّى أَنَا الْغَفُورُ الرَّحِيمُ - وَأَنَّ عَذَابِى هُوَ الْعَذَابُ الاٌّلِيمُ
(Declare to My servants, that I am truly the Oft-Forgiving, the Most Merciful. And that My torment is indeed the most painful torment.) meaning, `O Muhammad, tell My servants that I am the source of mercy and I am the source of punishment.' Similar Ayat to this have already been quoted above, which indicate that we must always be in a state between hope (for Allah's mercy) and fear (of His punishment).