瑜伽論記 19.35

19.35

十八明七法，為欲證得三摩地者，應正了知。景云：一、內定退因，謂懈怠者，由內心懈怠故起惛沈睡眠，故懈怠為因；二、外定退因，謂掉舉者，由於外境掉舉為因，取於五欲散亂；三、內定退，謂惛沈睡眠者，從懈怠生惛沈等正是其退，是未得退或是已得退，內緣為障名內；四、外定退，謂於五欲妙散亂者，由外掉舉取於五欲亦通二退，外緣為障名外；五、內定退、及因對治，謂善取相而正觀察者，由善取境界相，能離懈怠惛沈睡眠；六、外定退、及因對治，謂即於身觀察不淨者，觀自他身以為不淨能除掉舉五欲；七、彼二對治依持，謂光明想者，初觀境相及不淨觀依光明想。

The eighteenth section explains seven dharmas that should be correctly understood by one who wishes to realize samādhi. Jing says: first, the cause of internal deterioration of concentration, namely indolence: because of indolence in the internal mind, lethargy and sleep arise, hence indolence is the cause; second, the cause of external deterioration of concentration, namely agitation: because of agitation toward external objects as the cause, one grasps at distraction regarding the five desires; third, internal deterioration of concentration, namely lethargy and sleep: arising from indolence, lethargy and so forth are precisely the deterioration, either deterioration of what has not yet been attained or of what has already been attained; being hindered by internal conditions, it is called internal; fourth, external deterioration of concentration, namely distraction regarding the sublime five desires: grasping at the five desires due to external agitation also applies to both kinds of deterioration; being hindered by external conditions, it is called external; fifth, the antidote to internal deterioration of concentration and its cause, namely properly grasping signs and correctly observing: by properly grasping the signs of the objective sphere, one can leave indolence, lethargy, and sleep; sixth, the antidote to external deterioration of concentration and its cause, namely observing impurity in the body itself: observing one's own and others' bodies as impure can eliminate agitation and the five desires; seventh, the support and foundation of those two antidotes, namely the perception of light: the initial observation of objective signs and the observation of impurity rely upon the perception of light.