Murillo depicted Saint John the Baptist many times, almost always as a child with a lamb, a symbol of Christ. This work is the companion piece to the 'Infant Christ as the Good Shepherd' (private collection), whose history it shared until 1840. The two pictures decorated the altar erected in the Plaza de Santa María la Blanca in Seville during the festivities for the church's inauguration in 1665, and were painted shortly before.
The inscription is taken from the New Testament (John 1: 29 and 36).