首楞嚴義疏注經 4.367

4.367

天王，佛也。賜與，開示也。華屋，藏體也。雖獲，信解也。門入，修行也。行能通理故云門也。

The heavenly king is the Buddha. The grant is the revelation. The magnificent mansion is the substance of the treasury. Having obtained is faith and understanding. Entering by the door is practice. Practice can access principle, hence it is called a door.