Sayyiduna Abu Sa‘id Khudri (may Allah be pleased with him) narrates: By the One Who honored you (O Prophet) and revealed the Book to you! I saw the Messenger of Allah (peace and blessings be upon him) one night; he was leading the Maghrib prayer, and the tip of his forehead and nose were in water and mud (clay).
Hadith Referenceالمنتقى ابن الجارود / كتاب الصلاة / 200