Musnad Abu Ya'la al-Mawsili 3:270

Muhammad ibn Bashar narrated to us, Ubayd Allah ibn Abd al-Majid narrated to us, Ubayd Allah ibn Abd al-Rahman ibn Mawhab narrated to us, from Isma'il ibn Awn ibn Ubayd Allah ibn Abi Rafi', from Abd Allah ibn Muhammad ibn Umar ibn Ali ibn Abi Talib, from his father, from Ali ibn Abi Talib, who said: I fought a battle on the day of Badr, then I came to the Prophet, may Allah bless him and grant him peace, and he was prostrating, saying: "O Living, O Sustainer." Then I went and fought, then I came, and the Prophet, may Allah bless him and grant him peace, was prostrating, saying: "O Living, O Sustainer." He said: Then Allah granted him victory.