The twelve gates were twelve pearls, each gate made of a single pearl. - Revelation 21:21, NIV
Pearls are formed when a small grain of sand becomes embedded in an oyster, irritating it. To soften the irritation, the oyster coats the grain of sand with a smooth layer of what is called mother of pearl. As long as the oyster can feel the irritation, it continues to coat the sand with layers of pearl. What kind of irritation would have been necessary to form the pearls that make up the gates to our heavenly city when they are so large they can fit into a wall that is two hundred feet thick?! It must have been more than just irritation. It must have been horrendous, severe suffering!
I wonder . . . are the pearls a reminder, every time you and I enter My Father’s House, that we enter only because of the intense suffering and death of God’s Son? Do those pearly gates reflect the Cross of Jesus Christ?
From Heaven: My Father's House