Musnad Abu Ya'la al-Mawsili 140:9

Abu al-Rabi' al-Zahrani narrated to us, Salam bin Sulaym narrated to us, from Zayd al-'Ammi, from Yazid al-Raqashi, from Anas, from the Prophet, peace and blessings of Allah be upon him, who said: "The sea was split for the Children of Israel on the day of Ashura."