If someone accuses us falsely or attacks our reputation in some way, we immediately become offensive. We have rights and stand up for them. We are angry at injustices, especially if they are against us. We want to be honored and revered. We may not think too highly of ourselves and may put ourselves down, but if someone else does we are ready to give them our fists figuratively or literally. In other words, we feel we must increase.
But John is filled with joy at the thought of his ministry decreasing because it means the Messiah is here (John 3:29-30). John is giving us the secret to a happy life. When all our decisions are based on what increases the view of Christ our hearts can be at rest. We no longer feel the need to endlessly defend ourselves.
Intrusting our lives and reputation to God brings peace and therefore joy.
