James now brings his teachings about the impact of the tongue to a close in chapter three:

With the tongue we praise our Lord and Father, and with it we curse men, who have been made in God’s likeness. 10 Out of the same mouth come praise and cursing. My brothers, this should not be. 11 Can both fresh water and salt water flow from the same spring? 12 My brothers, can a fig tree bear olives, or a grapevine bear figs? Neither can a salt spring produce fresh water.

James does not mean that the tongue can never be used for critical tasks — just read James 4 and 5. No, the issue is clear: the tongue can be used for good and bad and the teachers were using the tongue for bad when they should have been using it for good.

Humans are to spoken to and about and with as befits who they are: Eikons of God. Let us say it again: every person you meet, every person with whom you will engage in conversation — today and forever — is an Eikon of God. If we treat God with respect, we are treat every human being with respect. Why? They are the very likeness of God.

And humans, who are Eikons of God, are capable of doing both good and bad with their tongue: the tongue, James is saying, is designed by God to do good and to fit in the world of God and Eikons. Therefore, use it for what God has designed it.

James is pushing harder: if the tongue indicates source, bad use of tongue indicates bad source. It’s that serious for James.

Let the words of my mouth and the meditation of my heart be acceptable in your
sight,* O LORD, my strength and my redeemer.
Psalm 19:14