Musnad Abu Ya'la al-Mawsili 117:226

Zuhayr narrated to us, Yazid ibn Harun narrated to us, Hammad ibn Salamah informed us, from Thabit, from Anas, that Harithah went out as a spectator, and an arrow came to him and killed him. His mother said, "O Messenger of Allah, you know my position regarding Harithah. If he is in Paradise, I will be patient; otherwise, you will see what I shall do." He said, "O mother of Harithah, it is not one Paradise, but many gardens, and Harithah is in the best of them," or he said, "in the highest of Firdaws." Yazid said, "I am in doubt."