Muwatta Imam Malik Book of Jihad, Hadith 13

Yahya related to me from Malik from Nafi that when Abdullah ibn Umar gave something in the way of Allah, he would say to its owner, "When you reach Wadi'l-Qura, (on the outskirts of Madina) then it is your affair."

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ نَافِعٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّهُ كَانَ إِذَا أَعْطَى شَيْئًا فِي سَبِيلِ اللَّهِ يَقُولُ لِصَاحِبِهِ إِذَا بَلَغْتَ وَادِيَ الْقُرَى فَشَأْنَكَ بِهِ .