Transliteration
bāhya-sparśeṣv-asaktātmā vindaty-ātmani yat sukham |
sa brahma-yoga-yuktātmā sukham akṣayam aśnute || 21 ||
Translation
With the mind detached from external contacts, one finds happiness in the Self — with the mind engaged in the contemplation of Brahman [ātman] one enjoys endless bliss.
Purport
Continuing from last Shloka Bhagwan Krishna further explains all blissful state of enlightenment. The state of enlightenment is so full of joy that material happiness and desires appear very small. Therefore one who is in a state of self-realized the state is not affected by the influx of physical desires. He enjoys the bliss of this state constantly contemplating in the supreme.
This and earlier shlokas also gives that lack of self-realization or the devotion in God forces human to rely solely upon physical enjoyment as he does not anything more than that. Humans should try to know this fact that superior joy and bliss exist in the state of enlightenment and hence should try to achieve that.
