Question: How can we know we have exclusive and unswerving devotion?
Swamiji: If you get (understand) the answer to your question - it is not because of the way I have explained it nor is it because of the way you had put your question. It is only because of the Grace of God. A person who asks a question rarely captures all his thoughts and the person who hears the question usually does not understand the full purport of what he hears. He answers it on the basis of his understanding of the question. If the person who asks the question gets his answer it is because of the God's Grace. In fact, whatever happens in the world is only because of God's Grace. It is not because of the individual's effort.
People say that I have an effect on people. If I had an effect - it should have been on all. This is not so. Once I was thrown out of a train even though I had a confirmed ticket. So I as an individual have no effect. It all happens by the Grace of God. Neither the one asking the question is perfect nor the one answering it is perfect - it happens by the Grace of God. The work is done by God’s grace alone. Only He is and only He will remain.
Source: "Art of Living" by Swami Ramsukhdasji