Musannaf Ibn Abi Shayba 3:1937

Hafs ibn Ghiyath narrated to us, from Hajjaj, from Fudayl, from Ibrahim, and from Hammad, from Sa’id ibn Jubayr, that they both said: When the person in a state of major ritual impurity (junub) hears [the recitation of a prostration verse], he should perform ghusl (ritual bath), then prostrate.