Musnad Ahmad 25:1130

Husayn ibn al-Hasan narrated to us, Abu Kudaynah narrated to us, from ‘Ata’, from Abu al-Duha, from Ibn ‘Abbas, who said: The Messenger of Allah (may Allah bless him and grant him peace) woke up one day, and there was no water in the camp. A man came to him and said: "O Messenger of Allah, there is no water in the camp." He said: "Do you have anything?" He said: "Yes." He said: "Bring it to me." He brought him a vessel containing a little bit of water. He said: The Messenger of Allah (may Allah bless him and grant him peace) placed his fingers over the mouth of the vessel and spread his fingers. He said: Springs gushed forth from between his fingers. He commanded Bilal, and said: "Call out to the people: 'The blessed ablution.'"