And We will have removed whatever is within their breasts of resentment, [while] flowing beneath them are rivers. And they will say, "Praise to Allāh, who has guided us to this; and we would never have been guided if Allāh had not guided us. Certainly the messengers of our Lord had come with the truth." And they will be called, "This is Paradise, which you have been made to inherit for what you used to do."
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,
The third verse (42) mentions those who dutifully follow Divine injunctions as they are the people of Paradise and there they shall live forever.
Injunctions of the Shari'ah : Consideration of Convenience
But, along with the condition set forth for such people; that they believe and do good deeds - said there, in all mercy, was: لَا نُكَلِّفُ نَفْسًا إِلَّا وُسْعَهَا (Allah does not obligate anyone beyond his capacity). The purpose is to emphasize that good deeds - which is a condition for entry into Paradise - is really not something so difficult as would be beyond the ability of a man or woman. In fact, Allah Ta` ala has made the injunctions of the Shari'ah flexible and easy in every department of life. Leaves and concessions have been granted in every injunction keeping sickness, weakness, travel and other human needs under consideration.
The position in Hell will be that people who were friends in this world will hate and curse each other. But, the atmosphere in Heaven will be entirely different. Here, all people’s hearts will be open to each other. Fountains of love and well-wishing for others will emerge from every heart. For the man in Hell, his past will be a bitter memory, while for the man in Heaven his past will be a pleasant memory. The future life of evil people will start with their hearts being a graveyard of regret and frustration. Their past will be solely composed of bitter memories. In contrast to this, the condition of good people will be that their minds will be full of the remembrance of God on whom they had rightly relied. They will be happy to find the intimation given by the flag-bearers of Truth to be absolutely correct. They will thankfully recognize God’s grace in His having blessed them and inspired them to support those who summoned them to accept the Truth.
Uthmani text of the Madinah mushaf (King Fahd Complex). Translation: Saheeh International. Tafsir via Quran.com.