Skandapurana 6.3.189.15

6.3.189.15

pāvanāya jagaddhetoḥ sthito yasmācchaśiprabhaḥ .
atastu nṛpaśārdūla śveta ityābhidhīyate .. 189.15 ..

because he stood shining like the moon for the purification of the world, / therefore, O tiger among kings, he is called Śveta;