Guru means Sad-guru, otherwise he cannot take you back to godhead.
If you want to know the heart of Guru, then you should follow his instructions strictly. Then seeing your sincerity, he will reveal secrets before you.
If you follow exactly what Guru says, Guru will protect you from maya.
Remain a fool before Guru. Do what he says. Then see the result.
Guru sometimes chastises his disciples left and right, uses harsh words. Then again takes him near like a father. One should use everything to become Krishna Conscious.
In the last stage of the spiritual master's life, the devotees of the spiritual master should take preaching activities into their own hands. In this way the spiritual master can sit down in a solitary place and render nirjana-bhajana.