Mishkat al-Masabih

Abu Ayyub told that he heard the Prophet say, “Capitals will be conquered at your hands and you will have to raise companies in large armies. A man will be unwilling to join a company, so he will escape from his people and go round the tribes offering himself to them, seeking someone whose place he may take in such and such an expedition.* That man is a hireling to the last drop of his blood.” * This is the type of person who dislikes being sent on a warlike expedition, but who is quite willing to take someone else’s place if he is paid for it. Abu Dawud transmitted it.