In plain words
Unless the tāmasa is given up, the Principle is not seen; unless the rājasa is given up, Bhakti does not come; the sāttvika alone becomes the sādhana of Bhakti: listen, heroic son of Bhārata!
This whole world, made up of what is seen, is only the working of the three guṇas. Every man is the very embodiment of the three guṇas. How can a man who passes his daily life in these three guṇas become free of the three guṇas? So it is only when he recognises the good and the bad in the nature of the three guṇas that man can go beyond the three guṇas.
For ordinary men all three, the tāmasika, the rājasika and the sāttvika, are needed; without sleep man cannot live. Without deliberation, man takes part in no action. Without thinking it over, no man enters on any task. So this sleep, deliberation and consultation, all these are simply qualities of a tāmasic kind. Then again, in daily life man cannot live even for a moment without the rājasika. All desires are rājasika. Even longing to have God is rājasika. Without being a man of desire, no one becomes a seeker of Mokṣa. Desires of the world and desires for God alike do not arise in man without the rājasika. Desires may be of many kinds, but the nature of desire is one. So anger, hatred, envy, Ahaṅkāra, ostentation and all such qualities are qualities of a rājasic kind. Within this rājasika, the sāttvika lies contained. As the Sarasvatī flows unseen beneath, between the Gaṅgā and the Yamunā, so the sāttvika runs unseen between this rajoguṇa and tamoguṇa. Step by step, when we examine each guṇa in its own way, when we enter each path and walk along it, the sāttvika emerges in us. If we want the sāttvika, the tāmasika is one step. The rājasika too is a step. Only when we cross these two does the sāttvika emerge in us.