James 3:1–2 (ESV)
Not many of you should become teachers, my brothers, for you know that we who teach will be judged with greater strictness. For we all stumble in many ways. And if anyone does not stumble in what he says, he is a perfect man, able also to bridle his whole body.
 

Luke 6:43–45 (ESV)
For no good tree bears bad fruit, nor again does a bad tree bear good fruit, for each tree is known by its own fruit. For figs are not gathered from thornbushes, nor are grapes picked from a bramble bush. The good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil, for out of the abundance of the heart his mouth speaks.

James 3:2 (ESV)
For we all stumble in many ways. And if anyone does not stumble in what he says, he is a perfect man, able also to bridle his whole body.

1. When we stay connected to Jesus, we don’t have to worry about being perfect. He is in control.

James 3:3–6 (ESV)
If we put bits into the mouths of horses so that they obey us, we guide their whole bodies as well. Look at the ships also: though they are so large and are driven by strong winds, they are guided by a very small rudder wherever the will of the pilot directs. So also the tongue is a small member, yet it boasts of great things. How great a forest is set ablaze by such a small fire! And the tongue is a fire, a world of unrighteousness. The tongue is set among our members, staining the whole body, setting on fire the entire course of life, and set on fire by hell. 

2. Our tongue reveals the trajectory of our heart and our maturity as believers.

Proverbs 15:4 (ESV)
A gentle tongue is a tree of life, but perverseness in it breaks the spirit.

Proverbs 18:20–21 (ESV)
From the fruit of a man’s mouth his stomach is satisfied; he is satisfied by the yield of his lips. Death and life are in the power of the tongue, and those who love it will eat its fruits.

James 3:7–12 (ESV)
For every kind of beast and bird, of reptile and sea creature, can be tamed and has been tamed by mankind, but no human being can tame the tongue. It is a restless evil, full of deadly poison. With it we bless our Lord and Father, and with it we curse people who are made in the likeness of God. From the same mouth come blessing and cursing. My brothers, these things ought not to be so. Does a spring pour forth from the same opening both fresh and salt water? Can a fig tree, my brothers, bear olives, or a grapevine produce figs? Neither can a salt pond yield fresh water.

Luke 6:43–49 (ESV)
For no good tree bears bad fruit, nor again does a bad tree bear good fruit, for each tree is known by its own fruit. For figs are not gathered from thornbushes, nor are grapes picked from a bramble bush. The good person out of the good treasure of his heart produces good, and the evil person out of his evil treasure produces evil, for out of the abundance of the heart his mouth speaks.

Why do you call me “Lord, Lord,” and not do what I tell you?  Everyone who comes to me and hears my words and does them, I will show you what he is like:  he is like a man building a house, who dug deep and laid the foundation on the rock. And when a flood arose, the stream broke against that house and could not shake it, because it had been well built. But the one who hears and does not do them is like a man who built a house on the ground without a foundation. When the stream broke against it, immediately it fell, and the ruin of that house was great.

3. Obedience to Jesus is how he transforms our heart.

James 3:13–18 (ESV)
Who is wise and understanding among you? By his good conduct let him show his works in the meekness of wisdom. But if you have bitter jealousy and selfish ambition in your hearts, do not boast and be false to the truth. This is not the wisdom that comes down from above, but is earthly, unspiritual, demonic. For where jealousy and selfish ambition exist, there will be disorder and every vile practice. But the wisdom from above is first pure, then peaceable, gentle, open to reason, full of mercy and good fruits, impartial and sincere. And a harvest of righteousness is sown in peace by those who make peace.

Exodus 33:12–23 (ESV)
Moses said to the Lord, “See, you say to me, ‘Bring up this people,’ but you have not let me know whom you will send with me. Yet you have said, ‘I know you by name, and you have also found favor in my sight.’ Now therefore, if I have found favor in your sight, please show me now your ways, that I may know you in order to find favor in your sight. Consider too that this nation is your people.” And he said, “My presence will go with you, and I will give you rest.” And he said to him, “If your presence will not go with me, do not bring us up from here. For how shall it be known that I have found favor in your sight, I and your people? Is it not in your going with us, so that we are distinct, I and your people, from every other people on the face of the earth?”

And the Lord said to Moses, “This very thing that you have spoken I will do, for you have found favor in my sight, and I know you by name.” Moses said, “Please show me your glory.” And he said, “I will make all my goodness pass before you and will proclaim before you my name ‘The Lord.’ And I will be gracious to whom I will be gracious, and will show mercy on whom I will show mercy. But,” he said, “you cannot see my face, for man shall not see me and live.” And the Lord said, “Behold, there is a place by me where you shall stand on the rock, and while my glory passes by I will put you in a cleft of the rock, and I will cover you with my hand until I have passed by. Then I will take away my hand, and you shall see my back, but my face shall not be seen.”

4. Heavenly wisdom keeps us humble and honors God.

James 3:17 (NIV)
But the wisdom that comes from heaven is first of all pure; then peace-loving, considerate, submissive, full of mercy and good fruit, impartial and sincere.