1. Custom implies continued observance of certain principle by persons or group of persons for a long time. Time is no consideration; declaration of sovereign command is legislation.
Custom is de-facto while legislation is de-jure.
Legislation set the relation between state and its subject, custom regulate relations among subject inter se.
For legislation existence of state is essential, custom does not need such agency.
Custom is the chief of characteristic of primitive society while legislation is a modern concept.