金光明經文句記 4.107

4.107

二、釋猶如空聚。無明業力，業即是行，乃無明緣行也。或初作業時，或託胎時，如向所明男女之識，於父母起貪瞋，以父母流謂是已有，乘茲妄念故得託胎。體即遺體，謂赤白也。

Second, explaining "like an empty village." The karmic power of ignorance: karma is volitional formations (saṅkhāra), namely, volitional formations conditioned by ignorance. Either when first creating karma, or when entering the womb, as explained earlier regarding the consciousness of male and female giving rise to greed and anger toward parents, and regarding the parents' discharge as one's own, by virtue of this deluded thought one is conceived in the womb. The "substance" is the parental bodily remains, namely the red and white.