Full Idea
The definition of 'injustice' is no other than the not performance of covenant….. and 'justice' is the constant will of giving to every man his own.
Gist of Idea
Injustice is the failure to keep a contract, and justice is the constant will to give what is owed
Source
Thomas Hobbes (Leviathan [1651], 1.15)
Book Reference
Hobbes,Thomas: 'Leviathan', ed/tr. Macpherson,C.B. [Penguin 1981], p.202