وَالَّذِينَ آمَنُوا وَعَمِلُوا الصَّالِحَاتِ أُولَٰئِكَ أَصْحَابُ الْجَنَّةِ ۖ هُمْ فِيهَا خَالِدُونَ
Wallazeena aamanoo wa 'amilus saalihaati ulaaa'ika as-haabul jannati hum feehaa khaalidoon
And those who believe and do righteous deeds — they are the companions of the garden, abiding there forever.
This is the counterpart clause, and its brevity is the point, since the warning it answers took longer to state than the promise does. The conditions are two, belief and righteous work, and they are the same two the universal verse named twenty lines earlier in this surah. Nothing is added about degree or measure, which leaves the reward described only by its permanence.