What is the ruling on seeking refuge with Allah when passing by a verse of punishment during a fard prayer, and what is the ruling on responding to some Quranic verses, such as (Is not Allah the most just of judges?) by saying: Indeed, and I am among those who bear witness to that? Does this invalidate the prayer?

It is sunnah (definition) for the reciter, both within and outside of prayer, whether he is an imam, a follower, or praying alone, according to the Shafi'is and Hanbalis, if he passes by a verse of mercy, to ask Allah for mercy, or by a verse of punishment, to seek refuge in Him from punishment, or by a verse of glorification, to glorify Him. As for the worshipper's saying: "Yes, and I am one of those who bear witness to that," after reciting (95:8) "Is not Allah the most just of judges?", it came in a weak hadith (definition), but it does not invalidate the prayer according to the Hanbalis and Malikis.