Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.052D.

The companions were all agreed that it is forbidden to touch or carry the Qur’an while one is in a state of impurity. There are some jurists, such as Dawud ibn Hazm, who allow the physically unclean person, whether because of sex or menstruation, to touch or carry the Qur’an, and they see nothing wrong with this. He derives his support from a hadith in the two Sahihs in which it is stated that the Prophet sent a letter to Heraclius saying, “In the name of Allah, the Compassionate, the Merciful…O people of the book, come to a statement that is common between us and you, that we should worship none but Allah, and that we shall ascribe no partner unto Him, and that none of us shall take others for lords besides Allah. If they turn away, then say ‘Bear witness that we are they who have surrendered (unto Him).” (al’Imran 64). Ibn Hazm concludes, “This is the letter the Messenger of Allah wrote, containing this verse, to the Christians, and of course they touched it.” The majority of scholars answer him by stating that one is allowed to touch parts of the Qur’an that are used in letters, books, tafsir, and so on, as such things are not copies of the Qur’an, nor is it confirmed that such an action is forbidden.