CC Madhya 9.90

kṛṣṇa-nāma vinā keha nāhi kahe āra
sabe kṛṣṇa-bhakta haila, — loke camatkāra
Word for word: 
kṛṣṇa-nāma vinā — without chanting the Hare Kṛṣṇa mahā-mantra; keha — anyone; nāhi — does not; kahe — speak; āra — anything else; sabe — all of them; kṛṣṇa-bhakta — Lord Kṛṣṇa’s devotees; haila — became; loke — the people; camatkāra — astonished.
Translation: 
Indeed, they did not chant anything but the Hare Kṛṣṇa mahā-mantra, and all of them became Lord Kṛṣṇa’s devotees. Thus the general populace was astonished.