觀無量壽佛經疏 3.176

3.176

三、從如先所說下，至非心力所及已來，正明境大心小卒難成就。致使聖意悲傷勸觀於小。

Third, from “as explained before” down to “not within the reach of mental capacity,” it directly explains that the object being large and the mind being small, it is difficult to accomplish suddenly. This causes the holy mind to grieve with compassion and urge contemplating what is small.