Is it permissible to say, "Yes, and I am among those who bear witness to that" during prayer as an affirmation of some of the verses being recited?

It is recommended for someone who recites a verse of mercy in prayer to ask Allah for His bounty, and upon reciting a verse of punishment, to seek refuge in Him from the Fire, based on the hadith (definition) of Ibn Abbas. Similarly, it is recommended for someone who recites: "Is not He able to give life to the dead?" to say: "Glory be to You, yes indeed," and this has been narrated from the Prophet, peace and blessings be upon him. This is recommended for everyone, whether the Imam, the congregant, or one praying alone, and also when reciting outside of prayer.