Proverbs 13:14 says, “The teaching of the wise is a fountain of life” (cf. 16:22). So, if the “teaching of the wise” is a fountain of life, and “the mouth of the righteous” is a fountain of life, then one element in this righteousness is true wisdom. Righteous people are people who live by the true wisdom of God’s Word. Then I remembered that the most crucial thing Proverbs says about wisdom is that “The fear of the Lord is the beginning of wisdom” (9:10). So, you have to assume that “the fear of the Lord” is right at the heart of the wisdom which is the basis of the way righteous people live (fear of the Lord—wisdom—righteousness). The surprising thing was the way this was confirmed in Proverbs 14:27, “The fear of the Lord is a fountain of life.”
So, I conclude that the mouth of the righteous is a fountain of life (10:11) because righteousness is a life based on true wisdom which is a fountain of life (13:14), and true wisdom is a fountain of life because it begins with the fear of the Lord, which is a fountain of life (14:27). When you think about the fear of the Lord or when you look up Psalm 36:9. The fear of the Lord means at least two things:
1. It means we stand in awe of the majesty and power and justice and holiness and grace of God. We tremble at his Word (Isaiah 66:2); and 2. It means that we shudder with dread at the thought of how terrible it would be to forsake this great God. As Joseph said; “Why should I do such a thing and sin against my God!”
    So those who fear the Lord stay with the Lord. They love the fellowship of God more than anything. And because they stay with the Lord and don’t forsake him for broken cisterns in the world, their roots are in the eternal fountain of life, God himself. This is what Psalm 36:9 says: “You [God] give them to drink from the river of your delights. For with you is the fountain of life.”
    Now we are getting to the very bottom of things. Now we know why righteousness makes the mouth into a fountain of life. The reason is that righteousness is a life based on true wisdom, and true wisdom begins with the fear of the Lord, and the fear of the Lord roots people in God himself and keeps us close to him in personal fellowship, and God—and God alone—is the ultimate, self-replenishing, inexhaustible fountain of life. “The mouth of the righteous is a fountain of life” because GOD is a fountain of life and the righteous live on God.
    Why does this righteousness make FOUNTAINS out of our mouths and not factories? The answer is that righteousness means being rooted in God, not standing outside God trying to earn your way in with a list of behaviors. Biblical righteousness is not primarily a set of things that you do but rather it is whom you trust and whom you live with and whom you fear to forsake, and whom you learn from to be wise. Or to use the New Testament terminology, righteousness is “abiding in the vine” not working for the vine, but trusting the vine to work through you, and flow through you. Righteousness is being in Christ and living by faith in his power and grace and wisdom. That kind of relationship with God and his Son makes your mouth a fountain of LIFE. Jesus said, “Out of the abundance of the heart the mouth speaks,” (Matthew 12:34).

But there remains one question: How Does This Produce Life for Others?