“If anyone among you thinks he is religious, and does not bridle his tongue but deceives his own heart, this one’s religion is useless”

At first appearance, this verse does not appear related to the context, but indeed it does closely link to the previous verses. A consistent Christian life always shows up in practice. James now gives a specific example of applying truth to experience. We see this in two areas: First, the true Christian will control her mouth (v.26), and, secondly, she will reach out to those in need (v.27).

If anyone among you thinks he is religious,

The word “religious’ means someone careful to keep external service to God. A religious person here is a pious person, someone who is devoted to or worships God. He perceives himself as a godly person.

and does not bridle his tongue

The idea of “bridle” is control. We control a horse by a bridle. Here, it is the control of the tongue. A person who does not keep her mouth shut deceives her own heart. A person who can reign in her mouth is someone who can practice what they preach.

A clear manifestation of someone who is religious but not spiritual is someone who uses his mouth to run down others. This is because he does not apply truth to experience.

Principle:

Restraining one’s mouth is one way to apply truth to experience.

Application:

Non-spiritual people, who constantly censure and detract from others, do not operate on the principle of applying truth to experience. People who run down others and find fault in others, to lessen them in the eyes of others, deceive their own hearts, and engage in a useless exercise.

When we detract from others to make ourselves seem superior, we enter into the vanity of religion.

“I said, ‘I will guard my ways, Lest I sin with my tongue;
I will restrain my mouth with a muzzle,
While the wicked are before me’” (Psalm 39:1).

“Set a guard, O LORD, over my mouth;
Keep watch over the door of my lips” (Psalm 141:3).

“But I say to you that for every idle word men may speak, they will give account of it in the day of judgment” (Matthew 12:36).