Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: The Messenger of Allah (peace and blessings be upon him) would sit on the ground, eat on the ground, hold a goat between his legs (to milk it), and accept the invitation of a slave to a meal of barley bread.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12441