When you come before spiritual master, be prepared to get chastised. Spiritual Master's business is to do that. Shisya means who is ready is accept 'sashan' or ready dor getting chastisement.
Out of many millions of wandering living entities, one who is very fortunate gets an opportunity to associate with a bonafide spiritual master by the grace of Krishna. By the mercy of both Krishna and the spiritual masters, such a person receives the seed of the creeper of devotional service.
When a pure devotee or spiritual master speak, what he says should be accepted as having been directly spoken by the Supreme Personality of Godhead in the Parampara System. — Sri Caitanya Caritamrita, Antya Lila, 05.71.
In the Bhagavat culture worship of the spiritual master plays a very important role in our life.
It is dangerous for a spiritual master to accept almost any aspirant. Although it is an aspect of mercy, it is dangerous. The danger also depends on the spiritual potency of the particular guru. Without sufficient potency, a few offensive or faithless disciples can lead to the guru’s fall.