You are reading a tafsir for the group of verses 55:60 to 55:63

هَلْ جَزَاءُ الْإِحْسَانِ إِلَّا الْإِحْسَانُ (Is there any reward for goodness other than goodness?...55:60). Having described the two Gardens for the intimate believers, it is declared as a principle that a good deed attracts a good reward. The righteous believers will be blessed, therefore, with good rewards.