Mishkat al-Masabih 530

Abū Dharr reported that the Messenger of Allah said: ‘Pure earth is a means of purification for a Muslim, even if he finds no water for ten years. But when he finds water, let him touch his skin with it, for that is better.’ Aḥmad, al-Tirmidhī, and Abū Dāwūd transmitted it. Al-Nasāʾī transmitted a similar report only up to ‘ten years.’