संन्यासस्तु महाबाहो दुःखमाप्तुमयोगतः।योगयुक्तो मुनिर्ब्रह्म नचिरेणाधिगच्छति॥
sannyāsas tu mahā-bāho duḥkham āptum ayogataḥyoga-yukto munir brahma na cireṇādhigacchati
Word by word
The verse says
But setting action down is hard to reach without practice, Arjuna. The sage joined to practice reaches the infinite before long.
In plain words
Here is the reason for the ranking at 5.2.
Renunciation is not being rejected. It is being called hard to reach by the direct route.
And the way to reach it turns out to be the other road.
Where you've felt this · in failure
You decide to give up coffee, late nights and saying yes to everything, all starting Monday. By Thursday you have all three back. The giving up was not a bad idea. You simply had nothing underneath it to stand on while it happened.
Going deeper
Duḥkham āptum — painful to attain, hard to come by. Renunciation is being described as a summit rather than a starting point.
The logic follows from everything Chapter 3 established. You cannot actually stop acting; the machinery runs whether you consent or not. So a renunciation attempted from a standing start is a refusal aimed at something that is not going to stop.
What the practice of action does is different. It works on the holding rather than the doing, and when the holding has genuinely gone, the setting-down has already happened without being attempted.
So the two are not rival routes after all. One is the road and the other is where the road ends.
That reframes the whole question for a reader who has ever tried to give something up by force. The giving up is real, but it is a result, and results cannot be performed.