Shall
 

1 archaic    a : will have to : MUST

2 a   used to express a command or exhortation  b   used in laws, regulations, or directives to express what is mandatory “a vessel when under way shall carry at her stern a white light U.S. Code”; “it shall be unlawful for any person to keep any wild animal in captivity Maine Hunting & Trapping Laws”

 

Source:  Webster’s Third New Unabridged Dictionary

 

“As used in statutes, contracts, or the like, this word is generally imperative or mandatory. In common or ordinary parlance, and in its ordinary signification, the term ‘shall’ is a word of command, an one which has always or which must be given a compulsory meaning; as denoting obligation. The word in ordinary usage means ‘must’ and is inconsistent with a concept of discretion. It has the invariable significance of excluding the idea of discretion, and has the significance of operating to impose a duty which may be enforced, particularly if public policy is in favor of this meaning, or when addressed to public officials, or where a public interest is involved, or where the public or persons have rights which ought to be exercised or enforced unless a contrary intent appears.”

 

Source:  Black’s Law Dictionary, 6^th Edition

 

“Words of the Constitution are to be taken in natural and obvious sense, and not in sense unreasonably restricted or enlarged.” Martin v Hunter’s Lessee, 14 U.S. 304 (1816).