大方廣佛華嚴經隨疏演義鈔 43.66

43.66

疏「非唯不亂本定更增」者，下出增相。猪以穢身揩於金山，非唯不污，而令山色轉益明淨，斯乃外境之猪益定山之淨。

Regarding the commentary's phrase “Not only is it not disturbed, the original concentration is further increased”: below, the characteristics of increase are presented. When a pig rubs its filthy body against a golden mountain, not only does it not defile it, but it causes the mountain's colour to become increasingly bright and pure; this is the pig of the external sense object augmenting the purity of the mountain of concentration.