Skandapurana 5.113.67

5.113.67

tataḥ provāca deveśaḥ prārthayasva drutaṃ dvija..
yenābhīṣṭaṃ prayacchāmi yadyapi syātsudurlabham .. 67 .. ..

Then the Lord of gods said: “Quickly ask, O twice-born, / so that I may grant the desired [boon], even if it should be exceedingly difficult to obtain.”