Just to add to this, for those who have read Se Kinehiya, Sant Baba Harnaam Singh Ji Rampur Khera Wale did not have a physical/living master. He only worshipped Sri Guru Granth Sahib Ji Maharaj, a point which us made very clear throughout the book.
Now, I'm not saying a spiritual master is not needed. In fact I would say they are extremely beneficial, no doubt. But, as far as what we need is concerned, Sri Guru Granth Sahib Ji is all we need.
This point was also said by Sant Baba Waryam Singh Ji Ratwara Sahib Wale. That if you are unable to recognise whether or not someone is a saint, then don't worry. Only believe and bow to Sri Guru Granth Sahib Ji. That is enough.