Musannaf Ibn Abi Shayba 13:3275

Abu Bakr narrated to us, he said: Jarir narrated to us, from Mughira, from Hammad, who said: It is disliked for the *mudarib* (the manager of the capital) to say to his partner, "I will favor you with twenty dirhams or thirty." However, he saw no harm in him saying, "I will favor you with a third, or a quarter, or a sixth."