Srimad Bhagavatam Canto 10, Chapter 13, Text 25

SB 10.13.25

go-gopinam matrtasminn
asit snehardhikam vina
purovad asv api hares
tokata mayaya vina
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Previously, from the very beginning, the gopis had motherly affection for Krsna. Indeed, their affection for Krsna exceeded even their affection for their own sons. In displaying their affection, they had thus distinguished between Krsna and their sons, but now that distinction disappeared.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
The distinction between one’s own son and another’s son is not unnatural. Many elderly women have motherly affection for the sons of others. They observe distinctions, however, between those other sons and their own. But now the elderly gopis could not distinguish between their own sons and Krsna, for since their own sons had been taken by Brahma, Krsna had expanded as their sons. Therefore, their extra affection for their sons, who were now Krsna Himself, was due to bewilderment resembling that of Brahma. Previously, the mothers of Sridama, Sudama, Subala and Krsna’s other friends did not have the same affection for one another’s sons, but now the gopis treated all the boys as their own. Sukadeva Gosvami, therefore, wanted to explain this increment of affection in terms of Krsna’s bewilderment of Brahma, the gopis, the cows and everyone else.
Srimad Bhagavatam Canto 10, Chapter 13, Text 24
Srimad Bhagavatam Canto 10, Chapter 13, Text 26