In plain words
Those who give counsel seeking the good of the children are the true gurus
One must grow a broad outlook with no sense of difference. The ṛṣis regarded the sons born to them and the sons of their Prema in the school as sons alike, and gave the two of them equal teaching. Today, if the principal's son is writing an examination in a class, the principal is not appointed invigilator there. They will not put him in charge, fearing that out of Prema for his son he might tell him something. But in the ṛṣis' āśramas of old they did not show such distinctions. The want of the threefold purity is the root cause of this difference. Only when we have gained a pure citta through sādhana do we become fit for the place of the guru. Those who give counsel seeking the good of the children are the true gurus. What are true disciples like? They are those who know nothing but eagerness for the guru and Bhakti towards him.