O Maharaja Pariksit, while the cowherd boys, who knew nothing within the core of their hearts but Krsna, were thus engaged in eating their lunch in the forest, the calves went far away, deep into the forest, being allured by green grass - SB 10.13.12

Expressions researched:
"O Mahārāja Parīkṣit, while the cowherd boys, who knew nothing within the core of their hearts but Kṛṣṇa, were thus engaged in eating their lunch in the forest, the calves went far away, deep into the forest, being allured by green grass"

Srimad-Bhagavatam

SB Canto 10.1 to 10.13

O Mahārāja Parīkṣit, while the cowherd boys, who knew nothing within the core of their hearts but Kṛṣṇa, were thus engaged in eating their lunch in the forest, the calves went far away, deep into the forest, being allured by green grass.

SB 10.13.12, Translation

O Mahārāja Parīkṣit, while the cowherd boys, who knew nothing within the core of their hearts but Kṛṣṇa, were thus engaged in eating their lunch in the forest, the calves went far away, deep into the forest, being allured by green grass.