In plain words
Among these, the knower, whose devotion is for no other, is also the yogi whose union never breaks. He is the greatest. I am dear to him, and he is very dear to Me.
Word for word
Among them the knower, a devotee with no other [object], is also the unceasingly united yogin and is foremost. I am dear to him, and he too is exceedingly dear to Me.