David, with God’s assistance, his only weapon a pebble, slew the giant. God gives us, as our weapon, the rosary. This has proven efficacious in the battles of the Church against heretics and heathen armies. Examples: Albigenses; Turks at Lepanto and Belgrade; many epidemics abated or averted by the power of the rosary. This devotion is just as powerful for the individual and for the family.