www.bible.com/111/pro.18.21.niv
From the fruit of their mouth a person’ stomach is filled; with the harvest of their lips they satisfied. The tongue has the power of life and death, and those who love it will eat its fruit.-Proverbs 18:20-21
Solomon, the wisest man (outside of Jesus) to walk the earth, is telling us here to beware the power of our words. It may seem strange to read or hear that your words can cause life or death. And you are probably wondering how mere words can kill someone. Solomon here is not saying that your words can bring about physical life or physical death, but he is saying that your words can bring about spiritual life or spiritual death depending on how you use them. You see a wonderful picture of this in Ezekiel 37:1-14. If you are not familiar with this passage this is the passage where the prophet Ezekiel is shown a valley of dry bones and ask if this dry bones can come back to life. His reply is that only God knows. Then he is told to speak to these dry bones the words that God commanded him to say and when he does these dry bones began to reattach themselves together, but there is still no life in them. Then Ezekiel is told to speak words of life to those without life and life was restored to them. Ezekiel through his very words was able to restore spiritual life to those who were spiritually dead. Your words can have that very same power if you learn to tame your tongue. Use your words to speak life and not death. Remember your words have the power of life and the power of death.
The hand of the Lord was on me, and he brought me out by the Spirit of the Lord and set me in the middle of of a valley, it was full of bones. He led me back and forth among them, and I saw a great many bones on the floor of the valley, bones that were very dry. He asked me, “Son of man, can these bones live?” I said, “Sovereign Lord, you alone know.” Then he said to me, “Prophesy to these bones and say to them, ‘Dry bones, hear the word of the Lord! This is what the Sovereign Lord says to these bones: I will make breath enter you, and you will come to life. I will attach tendons to you and make flesh come upon you and cover you with skin; I will put breath in you, and you will come to life. Then you will know that I am the Lord.'” So I prophesied as I was commanded. And as I was prophesying, there was a noise, rattling sound, and the bones came together, ,bone to bone. I looked and tendons and flesh appeared on them and skin covered them, but there was no breath in them. Then he said to me, “Prophesy to the breath; prophesy, son of man, and say to it, ‘This is what the Sovereign Lord says: Come, breath, from the four winds and breathe into these slain, that they may live.'” So I prophesied as he commanded me, and breath entered them; they came to life and stood up on their feet-a vast army. Then he said to me: “Son of man these bones are the people of Israel. They say, ‘Our bones are dried up and our hope is gone; we are cut off. ‘ Therefore prophesy and say to them: ‘This is what the Sovereign Lord says: My people, I am going to open your graves and bring you up from them; I will bring you back to the land of Israel. Then you, my people, will know that I am the Lord, when I open your graves and bring you up from them. I will put my Spirit in you and you will live, and I will settle you in your own land. Then you will know that I the Lord have spoken, and I have done it, declares the Lord'”-Ezekiel 37:1-14 (NIV)