Among those four, the knower, who knows the truth, by virtue of knowing the truth is ever yoked, and is of single devotion, since he sees no other worthy of worship. So that one, of single devotion, is distinguished, comes to a special eminence, surpasses the rest. For since I, the Self, am dear to the knower, I am exceedingly dear to him; it is well known in the world that the Self is dear. Since, then, Vāsudeva is the Self of the knower, He is dear to him. And that knower is the very Self of Me, Vāsudeva, and so is exceedingly dear to Me. Are the other three, then, the afflicted and the rest, not dear to Vāsudeva? It is not so. Rather.

Of these the man of knowledge is the more distinguished. Why? 'Ever joined, of single devotion.' For him, who has Me alone for his thing to be attained, the union with Me is perpetual; while for the other two the union with Me lasts only until the attaining of what each longs for. And the man of knowledge has devotion to Me, the one alone; while the other two have devotion to what each longs for, and to Me as the means to it. So he alone is the more distinguished. Moreover, exceedingly dear to the man of knowledge am I. Here the word 'exceedingly' denotes the thing to be expressed: as I am dear to the man of knowledge, that cannot be expressed even by Me, the all-knowing and all-powerful, since his dearness is without measure. As of Prahlada, foremost among men of knowledge, it is said, 'but he, his mind attached to Krishna, as he was being bitten by the great serpents, did not feel his own body, abiding in the gladness of the remembrance of Him'; he too is dear to Me in just that way.

This is a brief sub-gloss. For a fuller reading of this verse, see Madhusūdana, Śaṅkara, or Rāmānuja above.

Devotion to one alone is single devotion (eka-bhakti). So it is said in the Garuda, 'devotion to Me alone and to nothing else, that is called single devotion'.