tam vidyad duhkha-samyoga-
sa niscayena yoktavyo
" Know that as yoga without mingling of sorrow. One should engage oneself in the practice of yoga with determination and with a happy mind"
Sa = therfore, niscayena = definitely, yoktavya = to be perormed, yogo = yoga, anirvinna = without sorrow, cetasa = mind. We have to definitely perform yoga, with a mind or with thoughts full of happiness. We should not do it with grief. We should do it as a pleasant task. Vidyad = know, tam = that. Here the word tam [that] is the answer to the various relative pronouns used in slokas 20, 21 1nd 22, namley, yatra [ sloka 20] = in which[ mind is involved], yat [sloka 21] = that [which is endless pleasure] and yam [sloka 22] = that which [ by acquiring]. All these are related to this word tam in this sloka 23 and so, yoga is the one in which our mind should be involved. Yoga gives endless pleasure and by acquiring yoga, nothing else is to be acquired or all other things are not worth acquiring. Dukha = grief or sorrow, samyoga = mingled, viyogam = without, yoga = yoga, samajnitam = is called. Sri Krishna tells that person who has practiced yoga, is having only happiness without a trace of sorrow. When one started the yoga, one was griefstricken. But after practicing yoga all his grief have vanished and only happiness remains and to indicate this change of state only, Sri Krishna has used the words dukha samyoga viyogam, instead of merely stating sukha as adjective for yoga. We can summarize the four slokas as:
- Mind involved in yoga, diverting from other activities [sloka 20]
- Yoga is the ultimate happiness, once accomplished will never slip from that [sloka 21]
- Yoga is the only valuable accomplishment, all other pleasures and acquisitions would appear trivial and inferior and no grief can shake [sloka 22]