When vairagya appears in the mind, it opens the gate to divine wisdom. From dissatisfaction with the sense objects and worldly sense enjoyments comes aspiration. From aspiration comes abstraction. From abstraction comes concentration of the mind. From concentration of the mind comes meditation or contemplation. From contemplation comes samadhi or self-realization. Without dissatisfaction or vairagya, nothing is possible.
Just as cultivation in a stony or arid land becomes absolutely fruitless, so also yogic practices and atmavichara, enquiry of the soul, done without vairagya becomes fruitless. Just as water, when it leaks into the rat holes instead of running into the proper channels in agricultural fields, becomes wasted and does not help the growth of plants, so also the efforts of an aspirant go to waste if he does not possess the virtue of vairagya. He gets no spiritual advancement.
There must be intense vairagya in the minds of aspirants throughout the period of their sadhana. Mere mental adhesion will not do for success in yoga. There must be intense longing for liberation, a high degree of vairagya as well as the capacity for sadhana, spiritual practice.