Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 19

Sanskrit:

धार्यमाणं मनो यर्हि भ्राम्यदश्वनवस्थितम् ।अतन्द्रितोऽनुरोधेन मार्गेणात्मवशं नयेत् ॥ १९ ॥

ITRANS:

dhāryamāṇaṁ mano yarhibhrāmyad āśv anavasthitamatandrito ’nurodhenamārgeṇātma-vaśaṁ nayet

Translation:

Whenever the mind, being concentrated on the spiritual platform, is suddenly deviated from its spiritual position, one should carefully bring it under the control of the self by following the prescribed means.

Purport:

Although one is seriously engaging the mind in Kṛṣṇa consciousness, the mind is so flickering that it may suddenly be deviated from its spiritual position. One should then carefully bring the mind back under the control of the self. It is stated in Bhagavad-gītā that if one is too austere or too sensuous one cannot control the mind. Sometimes one may bring the mind under control by allowing the material senses limited satisfaction. For example, although one may eat austerely, from time to time one may accept a reasonable amount of mahā-prasādam, opulent foods offered to the temple Deities, so that the mind will not become disturbed. Similarly, one may occasionally relax with other transcendentalists through joking, swimming and so forth. But if such activities are performed excessively, they will lead to a setback in spiritual life. When the mind desires sinful gratification such as illicit sex or intoxication, one must simply tolerate the mind’s foolishness and by strenuous effort push on with Kṛṣṇa consciousness. Then the waves of illusion will soon subside, and the path of advancement will again open wide.