Do you like honey? It's sweet and gives you energy, right? And have you ever sucked on a sour lemon with no sugar? Ugh! It even gives you a bad chill.
The Bible says that the things that come out of our mouth are just like food. When we say kind things ("thank you," "you can do it," "I love you," "sorry"), it's like giving someone a spoonful of honey. They feel happy and strong. But when we say mean things (name-calling, yelling, ugly nicknames), it's like giving them a sour lemon or spoiled food. The person feels sad and "sick" on the inside.