(Thwaha) 20 : 76
جَنَّاتُ عَدْنٍ تَجْرِي مِنْ تَحْتِهَا الْأَنْهَارُ خَالِدِينَ فِيهَا ۚ وَذَٰلِكَ جَزَاءُ مَنْ تَزَكَّىٰ
Gardens of perpetual residence beneath which rivers flow, wherein they will abide forever. And that is the reward of one who purifies himself.
One can only purify his soul with Adhikr which is Food, Cloth, and Sight of the human soul as explained in verse 7: 26. And Without the Permission of Lord Adhikr, nobody can become a believer as explained in verses 10: 99-100. See explanation 4: 1 and 7: 205-206.