The Book of James teaches that a person's spiritual condition is often expressed by their tongue. In James 1:26, the Bible reads: "If any man among you seem to be religious, and bridleth not his tongue, but deceiveth his own heart, this man's religion is vain."
You can get into a lot of trouble with an unbridled tongue, and this tongue can destroy relationships, friendships, and reputations and deliver wounds that cannot be healed. A slack tongue is typically a sign of a lax life where personal and spiritual discipline is lacking.
I am reminded of a passage that our Lord Jesus said in Matthew 12:34, "Out of the abundance of the heart the mouth speaketh." James describes the person who goes to church, tithes, and says amen, yet they backbite, gossip, gripe, condemn, complain, insult, and injure with their slack tongue. They are tricking their own heart with all their religious activity.
We are challenged by Brother James here to examine ourselves and look at the authenticity of our faith. We must ensure that our tongues are bridled, and the blood of Jesus covers our hearts! Amen!