This knowledge is the possession of a Brahmana in particular by virtue of his birth. Knowledge of the Soul, and happiness like above, are each fully sufficient to lead to Liberation.
एतद् वै जन्मसामर्थ्य ब्राह्मणस्य विशेषतः। आत्मज्ञानं शमश्चैव पर्याप्तं तत्परायणम्॥