All our senses must be employed in service of Krishna

So all together there are sixty-four items for discharging the regulative practice of devotional service. Out of these sixty-four items, five items—namely worshiping the Deity, hearing Srimad-Bhagavatam, associating among the devotees, sankirtana, and living in Mathura—are very important.
The sixty-four items of devotional service should include all of our activities of body, mind and speech. As stated in the beginning, the regulative principle of devotional service enjoins that all of our senses must be employed in the service of the Lord. Exactly how they can be thus employed is described in the above sixty-four items. Now, Srila Rupa Gosvami will give evidence from different scriptures supporting the authenticity of many of these points.

Nectar of Devotion, Chapter 6