Nafi' (may Allah have mercy on him) said that Sayyiduna Ibn Umar (may Allah be pleased with them both) used to borrow the wealth of the orphans that was in his care, because he considered this safer for it against loss, and he also used to pay zakah from their wealth.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10987