Musannaf Ibn Abi Shayba 3:2647

Hushaym narrated to us, he said: Ubaydah informed us, from Abu Wa'il, who said: They mentioned the washing (ghusl) for the day of Friday in his presence. Abu Wa'il said: "It is not obligatory. How many an old man, if he were to wash in the intense cold on the day of Friday, would die."