Firm conviction that one should execute the order of the Lord is known as faith. One who has faith is firmly convinced that simply by rendering devotional service to Lord Kṛṣṇa all other activities are automatically performed, including ritualistic duties, sacrifices, yoga and the speculative pursuit of knowledge. In fact, devotional service to the Lord includes everything. As stated in Śrīmad-Bhāgavatam (4.31.14):
- yathā taror mūla-niṣecanena
- tṛpyanti tat-skandha-bhujopaśākhāḥ
- prāṇopahārāc ca yathendriyāṇāṁ
- tathaiva sarvārhaṇam acyutejyā
"By watering the root of a tree, one automatically nourishes the branches, twigs, leaves and fruits, and by supplying food to the stomach, one satisfies all the senses. Similarly, by rendering devotional service to Kṛṣṇa, one automatically satisfies the requirements for all other forms of worship and all other spiritual processes." One who is faithful and firmly convinced of this is eligible to be elevated as a pure devotee.