Sankhya-yoga is impractical because soul is always active
Everyone is forced to act helplessly according to the qualities acquired from the modes of material nature
Therefore no-one can refrain from doing something, not even for a moment
aPremature sannyasa is harmful
Premature renunciation is harmful because soul is always active
Either it has to be engaged in service of Krishna or
Under illusory energy where it may acquire three modes
bThus this verse sets criteria on when one should take sannyasa
Depending on the kind of modes one is affected by, sastras present different prescribed duties
to purify us from affinity of modes
to bring us to the level of jnana, with the knowledge of difference between body and soul
Thus when sufficiently purified, one can take sannyasa
c“Ultimate goal of Sannyasa, or any purificatory processes is to reach to the point of becoming Krishna conscious" (Ref. SB 1.5.17)
dKrishna consciousness turns yoga-ladder into an elevator — Therefore contact with Krishna (through contact with devotee) at any step of yoga ladder will speed up the process of purification