When God said, "Let there be Light," there was light. The very word of God brought life into existence. When Jesus said, "Lazarus, come forth!" Lazarus stepped out of his grave. The word of our Lord Jesus returned life back to Lazarus who had been dead several days. Jesus himself has the words of life.
God created man in his image and gave him words as well. God gave mankind dominion over the earth. Part of the creative tool kit for that dominion is words. It wasn't until sin came into the world that man began to use words for destructive rather than creative purposes.
Consider this proverb: "With the fruit of a man's mouth his stomach will be satisfied; He will be satisfied with the product of his lips" (Prov 18:20).
The imagery in this proverb is agricultural or horticultural. It refers to what the mouth and lips produce as "fruit" and "product." In Hebrew, "product" refers to produce, revenue, or what your work produces.
You almost get the idea that words are like the harvest. Fruit trees mature and produce fruit after its kind, whether apples, pears, oranges, figs, etc. The crops in the field mature and produces after its kind, whether wheat, corn, or some other kinds of vegetables.
How and what they produce depends on several things. First of all, it depends on the seed that you sow. If you plant an seeds for berries or tomatoes, then that is what the plants will produce. If you plant thistles, weeds, and other such things, then that is what they will produces.
Second, it depends on how you tend the soil. At the beginning of the season, the farmer must plowed and turn over the soil. He has to remove rocks, weeds, and other impediments. He needs to keep the soil watered and fertilized.
When you create the right conditions, then the soil along with the seed will produce good, healthy, pleasing fruit will bring joy to the farmer and to those he shares with.
That is the way it is with our speech. Words can bring joy or despair, life or death, depending on what kind of words they are. The kind of words they are depends on what kind of seed and cultivation has taken place. The fruit of the lips are connected to the soil of the heart.
"But the things that proceed out of the mouth come from the heart, and those defile the man. For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders. These are the things which defile the man; but to eat with unwashed hands does not defile the man" (Mt 15:18-20).
This indicates that we need a change of heart. When we create the right conditions by cultivating our heart, then God causes the growth of good fruit. Cultivation of the heart involves practices such as Bible reading, prayer, fasting, reflection, fellowship, worship, accountability, service, hospitality, and practices such as these. These help to create the conditions by which God works to transform our hearts, which will transform our speech. When that happens, then our speech can do the good things God created it to do.