Musannaf Ibn Abi Shayba 27:98

Abu Mu'awiyah narrated to us, from al-A'mash, from Shamir, who said: The Messenger of Allah (may Allah bless him and grant him peace) prayed one day, and the wolves came and howled behind him. When the Messenger of Allah (may Allah bless him and grant him peace) turned away [from the prayer], he said: "These wolves have come to inform you that you should distribute to them from your wealth what is sufficient for them, or leave them, or else they will raid you." They said: "Leave them, let them raid us."