Lord sends bonafide guru for sincere souls

The Lord is seated in the heart of all living beings, and thus he knows very well the movements of all individual persons. As soon as the Lord finds that a particular soul is very eager to go back to Godhead, the Lord at once sends His bona fide representative. The sincere devotee is thus assured by the Lord of going back to Godhead. The conclusion is that to get the assistance and help of a bona fide spiritual master means to receive the direct help of the Lord Himself.

(SB 1.19.36 - Purport)