Khumayr bin Malik narrates: When the order was given for the mushafs to be changed, this displeased Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), and he said: "Whoever among you is able to hide away a mushaf, let him hide it, for whoever acts unfaithfully with anything will bring it on the Day of Resurrection."
Then Sayyiduna Abdullah (may Allah be pleased with him) said: "I recited seventy surahs of the Qur'an from the blessed mouth of the Messenger of Allah (peace and blessings be upon him) while Zayd was still a child. Shall I then abandon what I took from the blessed mouth of the Messenger of Allah (peace and blessings be upon him)?"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8402