CC Antya Lila 7.43 "The conjugal love of the gopīs
is the most exalted devotional service, surpassing all other methods of bhakti.
Therefore Lord Krishna is obliged to say, 'My dear gopīs, I cannot repay you.
Indeed, I am always indebted to you."
Prema-vilas - Ch 7. Text 126-127 by Srila Nityananda Das
"Feeling separation from Me, Radha and the gopis
have given up Their lives. Now I shall
also give up My life for her. You will
see me in that condition, O Lokanath."
Excerpted from Sri Krishna Kathamrita Bindu Issue No134
"With that prema they [gopis] have given up everything. [...]
By their love, Krishna's promise was broken. His pormise is -'As someone
approaches me I reciprocate accordingly' {Bg
4.11} Krishna never becomes indebted, He always repays his debts. But this
promise of his was broken by the gopis, because the gopis do not want anything,
how will he repay them?
[...]
{Bhag. 10.32.22} "I have become
completely indebted to you. I cannot pay you back, because you don't want
anything. What shall I do?"
To
pay back his debt he became Gaura, assuming the mood of Radharani is crying and
feeling acute pangs of separation from Krishna. This is Gaura. [...] As
Radharani is crying, crying, crying and drowning herself in this unfathomable
ocean of separation, similarly Gaura is burning himself with the fire of
separations from Krishna."