[20].Surah Taha [Tâ-Hâ]: Ayat 74-76

Ayat 74. Verily! Whoever comes to his Lord as a Mujrim (criminal, polytheist, disbeliever in the Oneness of Allah and His Messengers, sinner, etc.), then surely, for him is Hell, therein he will neither die nor live.

Ayat 75. But whoever comes to Him (Allah) as a believer (in the Oneness of Allah, etc.), and has done righteous good deeds, for such are the high ranks (in the Hereafter),

Ayat 76. 'Adn (Edn) Paradise (everlasting Gardens), under which rivers flow, wherein they will abide forever: such is the reward of those who purify themselves [(by abstaining from all kinds of sins and evil deeds) which Allah has forbidden and by doing all that which Allah has ordained)].

[Tafseer] The verses 20:74-76 are best construed as comments on the story of the converted Egyptians who had "purified themselves (from evil)". But some construe them as a continuation of their speech. But such as come to Him as Believers who have worked righteous deeds,- for them are ranks exalted,- Gardens of Eternity, beneath which flow rivers: they will dwell therein for aye: such is the reward of those who purify themselves (from evil). As the Egyptian magicians had done when they confessed the One True God.   

Hazrat Abu Sa`id Al-Khudri (May Allah be pleased with him) said: The Messenger of Allah [SAWW](PBUH) said, "Allah, the Rubb of honour and glory, will say to the inhabitants of Jannah: `O inhabitants of Jannah!' They will respond: `Here we are! At Your service, O our Rubb. All good is in Your Hand!' He will ask them: `Are you pleased?' They will reply: `Why should we not be pleased, O Rubb, when You have given us what You have not given to any of Your creatures?' Allah will say: `Shall I not give you something better than that?' They will ask: `O Rubb! What can be better than that?' Allah will say: `I shall bestow My Pleasure upon you and I shall never be displeased with you.'''

[Al-Bukhari Book 08,Chapter 76, Hadith # 557] 

Lesson : as mentioned above in Surah Taha Ayat 76."Paradise (everlasting Gardens), under which rivers flow, wherein they will abide forever:" The declaration about Allah being pleased with the dwellers of Jannah will certainly be the greatest of the boons and rewards of Jannah.