It is narrated from Sayyiduna Imran bin Husayn (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said to a man: "What prevented you from praying?" He said: O Messenger of Allah, I was in a state of janabah. He (peace and blessings be upon him) said: "Perform tayammum with earth; when you have finished, pray, and when you find water, take a ritual bath (ghusl)."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1048