Śrīla Prabhupāda mentions in one of the lectures that a living entity who has no service to Kṛṣṇa, is like the finger that’s been cut off from the hand. It has no purpose. It’s useless. A finger’s usefulness is only when it’s connected to the hand. Similarly, a devotee’s usefulness is when he is connected to Kṛṣṇa’s service.
MKV, Vol 8- Pg 42, Chanting with Feeling- January 17, 2014 -Baltic Festival