Is it permissible to quote verses from the Holy Quran and change some of their words to suit contemporary events, such as saying: "No reproach shall be on you this day; the revolution forgives you," even if the speaker does not intend to mock?

There is no harm in quoting verses from the Holy Quran for a specific occasion, provided that it does not involve any disrespect towards them. There is no harm in attributing forgiveness to a revolution, because what is meant is the pardon and forgiveness of its people. It has been established in the Quran that forgiveness can be attributed to people, as in His (Allah's) saying: (And those who avoid the major sins and immoralities, and when they are angry, they forgive), and His saying: (But whoever is patient and forgives, indeed, that is of the matters [requiring] determination), and His saying: (Tell those who have believed to forgive those who expect not the days of Allah), and His saying: (But if you pardon and overlook and forgive – then indeed, Allah is Forgiving and Merciful).