觀無量壽佛經疏 3.114

3.114

十三、從作是觀者下，至得念佛三昧已來，正明剋念修觀現蒙利益。斯乃群生障重，真佛之觀難階，是以大聖垂哀，且遣注心形像。

Thirteenth, from "Those who perform this contemplation" down to "attains the samādhi of recollecting the Buddha," it properly explains that by focusing one's thought and cultivating the contemplation, one presently receives benefits. This is because sentient beings have heavy obstacles, and the contemplation of the true Buddha is difficult to ascend to; therefore, the Great Sage, bestowing compassion, temporarily directs them to focus their minds on physical images.