The dust of the feet of a devotee, the water that has washed the feet of a devotee and the remnants of food left by a devotee are three very powerful substances.
The root cause of devotional service to Lord Krishna is association with advanced devotees. Even when one's dormant love for Krishna awakens, association with devotees is still most essential.
As far as the great devotees of the Lord are concerned, they can purify a degraded soul just by being them and what to speak of the benefits of their association.
It is imperative that one sincerely seeks the association of pure devotees and hears them patiently and submissively from any position of life.
One who is in knowledge of the Absolute Truth and free from all material desires becomes a pure devotee of the Lord.
A devotee should not be proud of his acquisitions. The symptoms of a devotee are meekness and humility. Although spiritually very advanced, he will always remain meek and humble, as Krishna Das Kaviraja Gosvami and all the other Vaisnavas have taught us by personal example. Caitanya Mahaprabhu taught that one should be humbler than the grass on the street and more tolerant than the tree. One should not be proud or falsely puffed up. In this way one will surely advance in spiritual life.