Musannaf Ibn Abi Shayba 28:973

Abu Usama narrated to us, he said: Ubaydullah narrated to us, from Nafi’, who said: When Ibn Umar would give a camel for the sake of Allah, he would stipulate to its owner that he should not exhaust it until it reached Wadi al-Qura or a point parallel to it on the road to Egypt. Once it passed that point, it was like his own property; he could do with it whatever he wished.