युञ्जन्नेवं सदाऽऽत्मानं योगी विगतकल्मषः।सुखेन ब्रह्मसंस्पर्शमत्यन्तं सुखमश्नुते॥
yuñjann evaṃ sadātmānaṃ yogī vigata-kalmaṣaḥsukhena brahma-sansparśam atyantaṃ sukham aśnute
Word by word
The verse says
Joining himself this way always, the practitioner with his stains gone easily reaches the boundless happiness of touching the infinite.
In plain words
One word in this verse is easy to read past.
Sukhena — easily, with ease.
After a chapter of seats and restraint and slowly-slowly, the arrival is described as easy.
Where you've felt this · in friendship
After the first year, the Sunday walk stopped needing any decision. Your friend does not talk himself into it and he has no streak to protect. He puts his boots on.
Going deeper
Sukhena is a strange word to find here and it is not a slip.
The chapter has asked for a great deal: solitude, a measured diet, a disciplined body, an endless returning of the mind. And then the reaching is described as easy.
Both are true, and anyone who has built a habit knows how. The difficulty is all at the front. What is effortful in month one is not effortful in year three, and the person doing it in year three is not being heroic.
So the chapter is not describing a permanent struggle. It is describing an entry cost, paid slowly, after which the thing runs on much less.
Brahma-saṁsparśam — the touch of the infinite. A contact word, and the same family the Gita used at 5.22 for the pleasures born of contact. There it produced things that begin and end. Here it produces something described as boundless.