Spiritual strength comes by the association of devotees whose instructions infuse us with faith in the goal.
Even if such association is not available by physical proximity, we should keep their instructions within our heart. Similarly, if somebody gives you something very valuable and it means a lot to you, you will put it in a prominent place in your residence so that you can see it regularly or use it regularly. You will not put it in the closet. Thus if Vaisnavas give something natural in the form of instructions, if it is valuable, we should put it in a prominent place. The most prominent place to put it is within the core of our heart. Those instructions will help us to remain steady on the path of devotion and prevent us from slipping again and again. Even though we are blind, we will still be able to make progress towards the goal because those instructions within the heart will lead us.
LFD Vol 3,Spiritual Strength Pg 136, 4th paragraph