September 29 is the feast of St. Michael and all Holy Angels. Saint Michael is a very powerful advocate in the fight against evil. The prayer to St. Michael, illustrated in the video below, is very affective against spiritual attack.
"Slavery ended in medieval Europe only because the church extended its sacraments to all slaves and then managed to impose a ban on the enslavement of Christians (and of Jews). Within the context of medieval Europe, that prohibition was effectively a rule of universal abolition. "— Rodney Stark