To God they were conformed to the image of his firstborn Son. God is building a temple of living stones, all of different shapes and sizes, but all to be fitted perfectly together by the master builder. No one will envy anyone else's position as each will only fit in his own place. Thirdly, these bricks were thoroughly burned . The purpose was to harden them.
Few things are sadder to see than indoctrinated members of sects.
They are literally like brick wallw. They have been thoroughly baked and hardened to make them resist all outside influences. The true child of God is strong, but not hard. His strength is the inward strength of the Holy Spirit. He does not need a hard impenetrable shell to protect his inner uncertainty.