Whenever ʿAbdullāh b. ʿAbbās – Allāh be pleased with them – saw a muṣḥaf (copy of the Qurān) decorated with silver or gold he would say:

Do you tempt the thief, when its beauty is in its inside?

Abū ʿUbayd Al-Qāsim b. Sallām, Faḍāʾil Al-Qurān article 907.