Musnad Ahmad 770:79

Muhammad ibn Yazid al-Wasiti narrated to us, al-Mujalid ibn Sa'id informed us, from al-Sha'bi, from Jarir ibn Abdullah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "When the tax collector (musaddiq) comes to you, do not let him depart from you except while he is satisfied."