Skandapurana 6.3.131.22

6.3.131.22

kṣaṇamātraṃ kṛte kārye sā dāsī ca bhavenmama .
tataḥ svasthoragāḥ sarve bhaviṣyatha yathāsukham .. 131.22 ..

Once the task is accomplished for even a moment, she will become my slave-girl.
Then all of you serpents will be at ease and live comfortably.”