whenever a surah is sent down there are some of them who say which of you did it increase in faith? as for those who have faith it increases them in faith and they rejoice.
وإذا ما أنزلت سورة فمنهم من يقول أيكم زادته هذه إيمانا فأما الذين آمنوا فزادتهم إيمانا وهم يستبشرون