大方廣佛華嚴經入法界品四十二字觀門 1.27

1.27

訖灑（二合）字時，入決擇息諸業海藏般若波羅蜜門，悟一切法窮盡性不可得故。

When pronouncing the letter KṢA (conjunct), one enters the perfection of wisdom door of discerning and pacifying the ocean treasury of all karmas, because one realizes that the exhaustible nature (kṣaya) of all dharmas cannot be apprehended.