大般若波羅蜜多經般若理趣分述讚 3.171

3.171

讚曰：無際者，深妙難知故，亦由三劫難修所得故，深般若名為無際，此成三身亦名無際。非是二乘凡夫等類、十地菩薩所能知故。

Commentary: "Limitless" means profound and subtle, difficult to know; also, being attained through cultivation over three kalpas, deep wisdom is called "limitless"; that which completes the three bodies is likewise called "limitless." This is because it cannot be known by ordinary beings, followers of the two vehicles, or even bodhisattvas of the ten grounds.