Musnad Ahmad 1258:1

Yunus ibn Muhammad narrated to us, he said: 'Abd al-Wahid ibn Ziyad narrated to us, he said: Layth—meaning ibn Abi Sulaym—narrated to me, he said: Tawus narrated to me, from Umm Malik al-Bahziyyah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The best of people during tribulation is a man who is secluded with his wealth, worshipping his Lord and fulfilling His right, and a man who is holding the head of his horse in the way of Allah, frightening them and they frighten him."