仁王護國般若波羅蜜多經疏 3.437

3.437

解曰：登高臺者，顯居頂也。菩薩位極，如彼頂故。從此第二明佛果位。

The commentary explains: Ascending the high terrace illustrates dwelling at the summit. The bodhisattva's stage is supreme, just like that summit. Here begins the second part, clarifying the position of the Buddha fruit.