Hadith 509680
Chapter 21: Jihad - كتاب الجهاد
حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ قَالَ نَهَى رَسُولُ اللَّهِ صلى الله عليه وسلم أَنْ يُسَافَرَ بِالْقُرْآنِ إِلَى أَرْضِ الْعَدُوِّ .
Yahya related to me from Malik from Nafi that Abdullah ibn Umar said that the Messenger of Allah, may Allah bless him and grant him peace, forbade travelling with a Qur'an in the land of the enemy. Malik commented, "That is out of fear that the enemy will get hold of it."
Reference Muwatta Malik 509680
USC-MSA web (English) reference : Book 21, Hadith 7