We're continuing through Paul's writing to Titus. Sound Doctrine must be believed, held, and used. It's necessary to both hold off those who would damage the collective church and protect the faith of individual church members. The church exists to proclaim the true gospel to unbelievers and to ensure healthy and safe growth and development of individual believers. So true teaching, inspired by the Holy Spirit who inspired the speaking and writing of God's Word, provides both a shield and a weapon.