na yatra sravanadini
kurvanti satvatam bhartur
yatudhanyas ca tatra hi
My dear King, wherever people in any position perform their occupational duties of devotional service by chanting and hearing [sravanam kirtanam visnoh SB 7.5.23], there cannot be any danger from bad elements. Therefore there was no need for anxiety about Gokula while the Supreme Personality of Godhead was personally present.
Sukadeva Gosvami spoke this verse to mitigate the anxiety of Maharaja Pariksit. Maharaja Pariksit was a devotee of Krsna, and therefore when he understood that Putana was causing disturbances in Gokula, he was somewhat perturbed. Sukadeva Gosvami therefore assured him that there was no danger in Gokula. Srila Bhaktivinoda Thakura has sung: namasraya kari' yatane tumi, thakaha apana kaje. Everyone is thus advised to seek shelter in the chanting of the Hare Krsna maha-mantra and remain engaged in his own occupational duty. There is no loss in this, and the gain is tremendous. Even from a material point of view, everyone should take to chanting the Hare Krsna mantra to be saved from all kinds of danger. This world is full of danger (padam padam yad vipadam [SB 10.14.58]). Therefore we should be encouraged to chant the Hare Krsna maha-mantra so that in our family, society, neighborhood and nation, everything will be smooth and free from danger