Custom as a source of law :

Custom is a habitual course of conduct observed uniformly and voluntarily by the people concerned under like circumstances.

Analytical school of Jurisprudence: Custom is a Historical material source of Law, not law itself. Customs not law until approved by judge. According to the Analytical school of law, Customs are not law until recognised by the sovereign or pronounced upon by a court attaching legal sanction to the customs. The main protagonist of this view are Austin and Gray.

Historical school of Jurisprudence: Custom is the formal source of law and precedent to legislation. According to this school of thought, custom is law per se (Law in itself). Custom is originated in Volksgeist .i.e, general will of the people or from common consciousness of the people. Custom came into existence due to necessity and convenience. The main protagonists of this school of thought are Savigny and Puchta.