首楞嚴義疏注經 9.45

9.45

初五句結前生後。《俱舍論》說「第四禪離八災患，謂尋、伺、苦、樂、憂、喜及出、入息。又不為三災所動，名不動地。」今云不逼，即離下位苦也。苦因下釋不逼所以。尋、伺、憂、喜等是苦之因，今既離之，故無逼迫。樂非常住者，別明樂支以對前苦，三禪雖得徹意地樂，然不常住，必須有壞，壞即成苦，此名壞苦。苦樂下，正明此天今第四禪苦樂俱捨，以一一地皆厭下苦麁障，忻上淨妙離。棄下苦樂名麁重相滅，得上地定名淨福性生，以此禪定唯一捨受，是福之體。既離下染，故名淨福。

The first five lines conclude what precedes and introduce what follows. The *Kośa* says, 'The fourth dhyāna is free from eight calamities: namely, vitarka, vicāra, suffering, bliss, grief, joy, and outgoing and incoming breaths. Moreover, it is not shaken by the three disasters, so it is called the Unshakable Ground.' Here, saying 'not oppressed' means freedom from the suffering of the lower stages. 'The cause of suffering' onward explains why it is not oppressed. Vitarka, vicāra, grief, joy, and the like are the causes of suffering; now that one is free from them, there is no oppression. 'Bliss is not permanently abiding' clarifies the bliss factor individually in contrast to the earlier suffering; although the third dhyāna attains bliss that penetrates the mental ground, it is nevertheless not permanently abiding and must undergo destruction, and destruction is suffering—this is called the suffering of change. 'Suffering and bliss' onward directly clarifies that in this heaven, now in the fourth dhyāna, both suffering and bliss are abandoned, for each ground reviles the coarse, obstructive suffering of the lower [stage] and rejoices in the pure, wondrous detachment of the upper. Casting off the suffering and bliss of the lower is called 'the coarse and heavy marks are extinguished'; attaining the concentration of the upper ground is called 'the nature of pure blessings arises.' Because this dhyāna concentration is solely the feeling of equanimity, it is the substance of blessings. Having abandoned lower defilements, it is called pure blessings.