There are appropriate and inappropriate ways to dress for weddings and other special occasions. We "dress for the occasion".
The Bible uses this analogy to describe how we can - and should - change our ways appropriately for life in the Kingdom of God.
As an ancient wedding host would provide special clothes for his guests, God has provided his children with new "clothes" - glorious new ones!
So we should get changed! We should "take off" the old, the dirty and the inappropriate and "put on" the new, the clean and the appropriate.
Matthew 22:10-14, Zechariah 3:1-7, Ephesians 4:22-31, Luke 15:18-23, Isaiah 61:10