PTS cs 26 ‘Venerable Nāgasena, those five qualities of space which you say he ought to have, which are they?’
‘Just, O king, as space is everywhere impossible to grasp; just so, O king, should it be impossible for the strenuous Bhikshu, earnest in effort, to be anywhere taken hold of by evil dispositions. This, O king, is the first quality of space he ought to have.
PTS cs 27 ‘And again, O king, as space is the familiar resort of Rishis, and ascetics, and gods, and flocks of birds; just so, O king, should the strenuous Bhikshu, earnest in effort, make his mind wander easily over all things with the knowledge that each individual (Saṁkhāra) is impermanent, born to sorrow, and without any abiding principle (any soul). This, O king, is the second quality of space he ought to have. PTS vp En 317
PTS cs 28 ‘And again, O king, as space inspires terror; just so, O king PTS vp Pali 388 , should the strenuous Bhikshu, earnest in effort, train his mind to be in terror of rebirths in any kind of existence. To seek no happiness therein. This, O king, is the third quality of space he ought to have.
PTS cs 29 ‘And again, O king, as space is infinite, boundless, immeasurable; just so, O king, should the righteousness of the strenuous Bhikshu, earnest in effort, know no limit, and his knowledge be beyond measure. This, O king, is the fourth quality of space he ought to have.
PTS cs 30 ‘And again, O king, as space does not hang on to anything, does not cling to anything, does not rest on anything, is not stopped by anything; just so, O king, should the strenuous Bhikshu, earnest in effort, neither in any way depend on, nor cling to, nor rest on, nor be hindered by either the families that minister to him, or the pupils who resort to him, or the support he receives, or the dwelling he occupies, or any obstacles to the religious life, or any requisites that he may want, or any kind of evil inclination. This, O king, is the fifth quality of space he ought to have. For it was said, O king, by the Blessed One, the god over all gods, in his exhortation to Rāhula, his son:
“Just, Rāhula, as space rests nowhere on anything, so shouldst thou practise thyself in that meditation which is like space. Thereby shall neither pleasant nor unpleasant sensations, as they severally arise, bear sway over thy heart.”’