Musannaf Ibn Abi Shayba 36:179

Shababa ibn Sawwar narrated to us, from Sulayman ibn al-Mughira, from Thabit, from Anas, who said: My paternal aunt’s son, Haritha, went out with the Prophet, may Allah bless him and grant him peace, on the day of Badr. He went out as a young boy, a spectator; he did not go out for fighting. An arrow struck him and killed him. My paternal aunt, his mother, came to the Messenger of Allah, may Allah bless him and grant him peace, and said: "O Messenger of Allah, my son Haritha—if he is in Paradise, I will be patient and seek reward, but if not, you will see what I will do." He said: "O mother of Haritha, it is many gardens, and Haritha is in the highest Firdaws."