After Allah mentioned the condition of the miserable ones, He then mentioned the condition of the happy ones, saying,
وَالَّذِينَ ءَامَنُواْ وَعَمِلُواْ الصَّـلِحَاتِ
(But those who believed, and worked righteousness) Their hearts have believed and they performed good deeds with their limbs and senses, as compared to those who disbelieved in the Ayat of Allah and were arrogant with them. Allah also said that embracing faith and implementing it are easy, when He said,
وَالَّذِينَ ءَامَنُواْ وَعَمِلُواْ الصَّـلِحَاتِ لاَ نُكَلِّفُ نَفْسًا إِلاَّ وُسْعَهَا أُوْلَـئِكَ أَصْحَـبُ الْجَنَّةِ هُمْ فِيهَا خَـلِدُونَ وَنَزَعْنَا مَا فِى صُدُورِهِم مِّنْ غِلٍّ
(But those who believed, and worked righteousness -- We burden not any person beyond his scope -- such are the dwellers of Paradise. They will abide therein. And We shall remove from their breasts any Ghill;) meaning, envy and hatred. Al-Bukhari recorded that Abu Sa`id Al-Khudri said that the Messenger of Allah ﷺ said,
«إِذَا خَلَصَ الْمُؤْمِنُونَ مِنَ النَّارِ حُبِسُوا عَلَى قَنْطَرَةٍ بَيْنَ الْجَنَّةِ وَالنَّارِ فَاقْتُصَّ لَهُمْ مَظَالِمَ كَانَتْ بَيْنَهُمْ فِي الدُّنْيَا حَتَّى إِذَا هُذِّبُوا وَنُقُّوا أُذِنَ لَهُمْ فِي دُخُولِ الْجَنَّةِ فَوَالَّذِي نَفْسِي بِيَدِهِ إِنَّ أَحَدَهُمْ بِمَنْزِلِهِ فِي الْجَنَّةِ أَدَلُّ مِنْهُ بِمَسْكَنِهِ كَانَ فِي الدُّنْيَا»
(After the believers are saved from entering the Fire, they will be kept in wait by a bridge between Paradise and Hellfire. Then, transgression that occurred between them in the life of this world will be judged. Until, when they are purified and cleansed, they will be given permission to enter Paradise. By He in Whose Hand is my soul! One of them will be able to find his dwelling in Paradise more so than he did in the life of this world.) As-Suddi said about Allah's statement,
وَنَزَعْنَا مَا فِى صُدُورِهِم مِّنْ غِلٍّ تَجْرِى مِن تَحْتِهِمُ الاٌّنْهَـرُ
(And We shall remove from their breasts any Ghill; rivers flowing under them,) "When the people of Paradise are taken to it, they will find a tree close to its door, and two springs from under the trunk of that tree. They will drink from one of them, and all hatred will be removed from their hearts, for it is the cleansing drink. They will take a bath in the other, and the brightness of delight will radiate from their faces. Ever after, they will never have messy hair or become dirty." An-Nasa'i and Ibn Marduwyah (this being his wording) recorded that Abu Hurayrah said that the Messenger of Allah ﷺ said,
«كُلُّ أَهْلِ الْجَنَّةِ يَرَى مَقْعَدَهُ مِنَ النَّارِ، فَيَقُولُ: لَوْلَا أَنَّ اللهَ هَدَانِي، فَيَكُونُ لَهُ شُكْرًا، وَكُلُّ أَهْلِ النَّارِ يَرَى مَقْعَدَهُ مِنَ الْجَنَّةِ فَيَقُولُ: لَوْ أَنَّ اللهَ هَدَانِي، فَيَكُونُ لَهُ حَسْرَة»
(Each of the people of Paradise will see his seat in the Fire and he will say, `Had not Allah guided me! And this will cause him to be grateful. Each of the people of the Fire will see his seat in Paradise, and he will say, `Might that Allah had guided me!' So it will be a cause of anguish for him.) This is why when the believers are awarded seats in Paradise that belonged to the people of the Fire, they will be told, "This is the Paradise that you inherited because of what you used to do. " This means, because of your good deeds, you earned Allah's mercy and thus entered Paradise and took your designated dwellings in it, comparable to your deeds. This is the proper meaning here, for it is recorded in the Two Sahihs that the Prophet said,
«وَاعْلَمُوا أَنَّ أَحَدَكُمْ لَنْ يُدْخِلَهُ عَمَلُهُ الْجَنَّة»
(And know that the good deeds of one of you will not admit him into Paradise.) They said, "Not even you, O Allah's Messenger" He said,
«وَلَا أَنَا إِلّا أَنْ يَتَغَمَّدَنِيَ اللهُ بِرَحْمَةٍ مِنْهُ وَفَضْل»
(Not even I, unless Allah grants it to me out of His mercy and favor.)