In plain words
Now the second instrument is speech. It is mighty in power. When we tell a man something sorrowful or alarming, he becomes weak. He collapses where he stands. The moment he hears this word he loses all his strength. A single word sucks up all his strength. When a good word or a joyful word is spoken, it gives that man the strength of an elephant. It is the word that gives strength and the word that makes one powerless. A word costs nothing. Its worth is great.