"And those who believe respond" that is: they respond to their Lord, believing in Him, "and He increases them from His bounty," meaning: the multiplication of good deeds.
Interpretation of Surah Ash-Shura from verse 27 to verse 31.
﴿ويستجيب الَّذين آمنُوا﴾ أَي: يستجيبون لرَبهم يُؤمنُونَ بِهِ ﴿ويزيدهم من فَضله﴾ يَعْنِي: تَضْعِيف الْحَسَنَات.
تَفْسِير سُورَة الشورى من الْآيَة ٢٧ إِلَى آيَة ٣١.