Musannaf Ibn Abi Shayba 28:344

Waki’ narrated to us, he said: Sufyan narrated to us, from Yahya ibn ‘Amr ibn Salamah al-Hamdani, from his father, from ‘Ubaydah al-Salmani, who said: ‘Umar said to me: "How much do you think is sufficient for a man from his stipend?" I said: "So and so." He said: "If I remain, I will surely make a man’s stipend four thousand: one thousand for his weaponry, one thousand for his expenses, one thousand he puts in his house, and one thousand for such and such." I think he said: "for his horse."