Prayer (Kitab Al-Salat): Detailed Injunctions about Witr
Dawud :: Book 8 : Hadith 1512
Narrated Zayd, the client of the Prophet:
The Prophet (peace_be_upon_him) said: If anyone says: "I ask pardon of Allah than Whom there is no deity, the Living, the eternal, and I turn to Him in repentance," he will be pardoned, even if he has fled in time of battle.