4 inches of power
The human tongue is only about 4 inches long, but it is a powerful part of the human body. It is the source of one of our senses - taste. It is part of the digestive process. It helps us chew and shallow our food. Psalm 139:14 says we are fearfully and wonderfully made. Romans 1:20 says we can understand the invisible things of the Creator through His creation. This is very true when it comes to the tongue. It is more than a small physical muscle. It represents great spiritual power.
When God created the heaven and the earth, there was not material from Him to work with, so He spoke everything into existence (Gen 1). God's words have creative power, and He upholds the creation with the word of His power (Heb 1:3). It is only by the word of God that we can be saved (Jn 6). The Bible is unique among all literature because only it is the written word of God (2Tim 3:15-17, 2Pet 1:19-21).
When God the birds, fish, animals, and then man, He made man unique. He made him a living soul in His image (Gen 1:27, Gen 2:7). Other creatures can communicate through sounds. Birds can be taught to mimic words, and apes can be taught rudimentary sign language; but only man has fully developed language. Man is uniquely designed physically for speech. God gave man this power as His highest creation in this world.
The old saying "sticks and stones may break my bones, but words will never hurt me" is not true. There is creative and destructive power in the words we speak. The book of Proverbs is amazing in its depth and breadth. It covers many different topics, but the one mentioned more than any other is the power of words, with 105 references. This book tells of the power of wise, righteous, true, knowledgeable, and good words. It also warns against forward, flattering, foolish, violent, lying, hypocritical, and contentious words. "Death and life are in the power of the tongue: and they that love it shall eat the fruit thereof (Prov 18:21)." Some of the best advice Proverbs offers us about our words is that sometimes it is best not to use them at all.
Jesus said that what is in the heart of man will make its way out through the tongue (Mt 12:34). However, this can also work the other way. We can uplift or destroy ourselves and others with the words we speak (Jam 3). We need to be careful what we say. Just because a thought crosses our mind does not mean we need to speak it. We add power to thoughts when we speak them, both good and bad. David wisely prayed, "Set a watch, O Lord, before my mouth; keep the door of my lips (Ps 141:3)."
God chose to save eternal souls through the spoken words of men (Rom 10:8-18, 1Cor 1:18-23). That is great power indeed. When the Lord appeared to Paul on the road to Damascus, Paul asked him what He should do (Acts 9). The Lord did not explain it to him. Instead He sent a preacher. When the angel appeared to Cornelius, he also did not tell him how to saved. He told him to send for Peter who would tell him (Acts 10-11). There is no greater honor, office, or responsibility than to bring the gospel to others. That is the greatest word one can ever speak - the word of God. We should memorize scripture so we can quote it in prayer, and use it to encourage and admonish ourselves and others. It is the living, eternal, truth of God.