By chanting the holy name of the Supreme Lord, one comes to the stage of love of Godhead. Then the devotee is fixed in his vow as an eternal servant of the Lord, and he gradually becomes very much attached to a particular name and form of the Supreme Personality of Godhead. As his heart melts with ecstatic love, he laughs very loudly or cries or shouts. Sometimes he sings and dances like a madman, for he is indifferent to public opinion.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
एवंव्रतः स्वप्रियनामकीर्त्या जातानुरागो द्रुतचित्त उच्चैः । हसत्यथो रोदिति रौति गाय- त्युन्मादवन्नृत्यति लोकबाह्यः
evaṃvrataḥ svapriyanāmakīrtyā jātānurāgo drutacitta uccaiḥ | hasatyatho roditi rauti gāya- tyunmādavannṛtyati lokabāhyaḥ
SB 11.2.40