Hammad bin Zayd حماد بن زيد بن درهم الأزدي الأزرق · The Book on Virtues of Jihad

I heard the Messenger of Allah (ﷺ) say: "Whoever shoots an arrow in the cause of Allah, then he has the reward of freeing a slave." This Hadith is Hasan Sahih. Abu Najih is 'Amr bin 'Abasah As-Sulami, and 'Abdullah bin Al-Azraq is 'Abdullah bin Zaid.