Shurahbil bin al-Simt (may Allah be pleased with him), who was the governor of Hims, said to Amr bin Abasah al-Sulami (may Allah be pleased with him), a Companion of the Prophet (peace and blessings be upon him): O Abu Najih! Narrate to us a hadith of the Messenger of Allah (peace and blessings be upon him) in which there is neither addition nor forgetfulness. He said: I heard the Messenger of Allah (peace and blessings be upon him) say: "Whoever frees a believing slave, Allah will free every limb of his from Hell. Whoever shoots an arrow at the enemy, that too is equal to freeing a slave. And whoever grows old in the path of Allah, it will be a light for him on the Day of Resurrection."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب العتق / 21310