It was June 17, 2015, when a young man entered the Emanuel AME Church in Charleston SC and began a shooting spree, killing 9 innocent worshipers, including the senior Pastor. The young man was apprehended then next day and is currently awaiting trial. Nov. 5, 2017: Dressed in black tactical-style gear and armed with an assault weapon, a 21-year-old opened fire at the First Baptist Church of Sutherland Springs, Texas, killing 26 people and wounding about 20 others.
Compare the above scenarios with that of December 9, 2007, when a young man attacked the New Life Church, a mega Church in Colorado Springs, Colorado, with a number of firearms, killing two and injuring three before being shot by Jeanne Assam, a member of the church's safety team, who was carrying a licensed private firearm. Emanuel in SC and First Baptist in Sutherland were small congregations and experienced many casualties, while the mega Church only had 2 deaths. The difference—a great emergency and security plan involving armed attendees in the Church.
Nine innocent people were killed in Charleston and 26 in Texas, but the Churches did not have an armed security team during services. What if there were several men/women that were carrying a concealed weapon and could have stopped the shooter when he brandished his weapon or fired the first shot? What if all licensed concealed carry members were allowed to bring their weapons to church? The scenario would have a different ending. Those seeking to do others harm are more reluctant to do so when they know others can shoot back.