Musnad Ahmad 1017:108

'Abd al-Samad and 'Affan narrated to us, they said: Hammad ibn Salamah narrated to us, from Sa'id al-Jurayri, from Abu Nadrah, from 'Abdullah ibn Mawlah, from Buraydah al-Aslami, that the Messenger of Allah (peace and blessings of Allah be upon him) said: "Let one of you be content in this world with a servant and a mount."