وَ  مَنْ  یُّطِعِ  اللّٰهَ  وَ  رَسُوْلَهٗ  یُدْخِلْهُ  جَنّٰتٍ  تَجْرِیْ  مِنْ  تَحْتِهَا  الْاَنْهٰرُ  خٰلِدِیْنَ  فِیْهَاؕ-وَ  ذٰلِكَ  الْفَوْزُ  الْعَظِیْمُ(۱۳)

And whosoever obeys Allah and His Messenger; Allah will take him into the Gardens beneath which rivers flow; (they) will abide in it forever; only this is the great success.

[Kanz-ul-Iman (translation of Quran)] (Part 4, Surah Al-Nisa, Verse 13)

At another place, He Almighty states:

فَمَنْ  زُحْزِحَ  عَنِ  النَّارِ  وَ  اُدْخِلَ  الْجَنَّةَ  فَقَدْ  فَازَؕ-

So, the one who is saved from the Fire and is admitted into Paradise is successful.

[Kanz-ul-Iman (translation of Quran)] (Part 4, Surah Aal-e-Imraan, Verse 185)

Under this verse, it is stated in Tafseer Siraat-ul-Jinan: We come to know that true success is that on the Day of Judgement, a person is saved from Hell and is given entry into Paradise. Whereas, although success in the world is success in itself, however, if this success is detrimental for the Hereafter, then in reality it is a loss. And in particular, those people who do everything to succeed in this world but do not do anything to succeed in the Hereafter, they are undoubtedly in loss. Therefore, every Muslim ought to give more attention towards and make more efforts for those actions that grant them true success, and avoid those actions that can become an obstacle on the path to true success. (Tafseer Siraat-ul-Jinan, Part 4, Surah Aal-e-Imraan, Taht-al-Ayah 185, vol. 2, p. 112)

Dear Islamic brothers! No doubt, the fortunate one is he who is saved from Hell. Fortunate is he who reaches the beautiful gardens of Paradise, fortunate is the one who is successful in having his Iman intact when leaving this world.