Total absorption in hearing Sankirtana Music develops faith in Lord Krishna.
Faith means… unflinching trust in something sublime.
Bhagavad Gita 2.41,
One is called a faithful man who thinks that simply by acting in Krishna consciousness he can attain the highest perfection.
Bhagavad Gita 4.39,
No one lives even a moment without faith, even unconsciously.
When we face difficulties and still remain faithful to Krishna and the spiritual master, we access the infinite mercy of their hearts.