When there is shivering of the body and the hairs of the body stand up, it is to be understood that the devotee is nearing perfection. An example of a sādhaka cultivating devotional service is Bilvamaṅgala Ṭhākura.
When a devotee is never tired of executing devotional service and is always engaged in Kṛṣṇa conscious activities, constantly relishing the transcendental mellows in relationship with Kṛṣṇa, he is called perfect. This perfectional stage can be achieved in two ways: one may achieve this stage of perfection by gradual progress in devotional service, or one may become perfect by the causeless mercy of Kṛṣṇa, even though he has not executed all the details of devotional service.