瑜伽論記 2.82

2.82

Later, the Supplement asks: When Śakra fought with the asuras, the upper four heavens each dispatched heavenly hosts to assist Śakra, guarding the four sides of Mount Sumeru. Why did they not fight with the asuras? The explanation is: they merely helped guard the citadel and did not fight together. If so, since the upper four heavens do not harm each other and do not kill asuras, they would have no killing karma.