Musnad Abu Ya'la al-Mawsili 152:66

On the authority of Abu Wa'il, he said: Abdullah said, "A man came to me today and asked me about a matter, and I did not know what to answer him. He said, 'What do you think of a man who is compliant and energetic, who goes out on military expeditions, and they (the commanders) compel us to do things from which we find no escape?' I said to him, 'By Allah, I do not know what to say to you, except that we were with the Messenger of Allah (peace and blessings of Allah be upon him), and he would rarely compel us to do a matter except once, until we performed it. And one of you will continue to be in a state of goodness as long as he fears Allah. And if he doubts something within himself, he asks a man, and he heals him (by providing an answer), and soon you will not find him. By the One besides Whom there is no god, I do not remember what has passed of the world except like a pool of water whose clear part has been drunk, and its dregs remain.'"