Transliteration
yadā hi nendriyārtheṣu na karmasv-anuṣajjate |
sarva saṅkalpa saṃnyāsī yogārūḍhas-tad-ocyate || 4 ||
Translation
When one loses all attachment for the sense-objects and to works, then one indeed has abandoned all desires and is considered to have reached the heights of Yoga.
Purport
In earlier Shloka Bhagvan Shri Krishna explained the stages where the Karma and Sanyas are dominant. In the process of yoga, karma should be the main tool. Once he attains the perfection Sanyas(Renunciation) becomes the means to go forward.
In this Shloka Bhagvan Shri Krishna explains the elements of the same. When a person starts his journey towards the enlightenment and starts by practicing Karma yoga sincerely, that is indulging in his duty or devotion by keeping his faith in offering his actions to supreme Shri Krishna soon he attains perfection. As he attains perfection, he loses the attachment to the sense of gratification and desires. Once he loses the attachment, practicing Sanyas becomes easier for him. If he also attains perfection in Sanyas then he becomes a real yogi.
The summary is that both Karma and Sanyas(renunciation) is an essential part of attaining enlightenment.
