Musnad Ahmad 907:115

Abdullah ibn Maymun Abu Abd al-Rahman al-Raqqi narrated to us, Ubayd Allah—meaning Ibn Amr—narrated to us, from Abd al-Malik ibn Umayr, from Jabir ibn Samurah, who said: I heard a man ask the Prophet, peace and blessings of Allah be upon him: "Should I pray in the garment in which I come to my wife?" He said: "Yes, unless you see something on it, then wash it."