Srimad Bhagavatam Canto 10, Chapter 82, Text 38

SB 10.82.38

etav adrsta-pitarau yuvayoh sma pitroh
 samprinanabhyudaya-posana-palanani
prapyosatur bhavati paksma ha yadvad aksnor
 nyastav akutra ca bhayau na satam parah svah
 
Translation: 
 
Before these two boys had ever seen Their real parents, you acted as Their parents and gave Them all affectionate care, training, nourishment and protection. They were never afraid, good lady, because you protected Them just as eyelids protect the eyes. Indeed, saintly persons like you never discriminate between outsiders and their own kin.
 
Purport: 
 
As Srila Visvanatha Cakravarti explains, Krsna and Balarama had not seen Their parents for two reasons: because of Their exile in Vraja, and also because They are never actually born and therefore have no parents.
 
Srila Visvanatha Cakravarti also describes what Devaki thought before speaking this verse: “Alas, because for so long these two sons of mine had you, Yasoda, as Their guardian and mother, and because They were immersed in such a vast ocean of ecstatic loving dealings with you, now that you are once more before Them They are too distracted to even notice me. Also, you are behaving as if insane and blind with love for Them, showing millions of times more maternal affection than I possess. Thus you simply keep staring at us, your friends, without recognizing us. So let me bring you back to reality on the pretext of some affectionate words.”
 
Then, when Devaki failed to get any response from Yasoda even after addressing her, Rohini said, “My dear Devaki, it’s impossible just now to rouse her out of this ecstatic trance. We are crying in the wilderness, and her two sons are no less bound up in the ropes of affection for her than she is for Them. So let us now go outside to meet with Prtha, Draupadi and the others.”
Srimad Bhagavatam Canto 10, Chapter 82, Text 37
Srimad Bhagavatam Canto 10, Chapter 82, Text 39