Historically, the Christian tradition from at least St. Thomas Aquinas forward has recognized three spheres of justice: the commutative, the legal, and the distributive. Commutative justice connotes justice between people. Arguing that all people have equal worth and dignity is a fundamental commutative principle. An important corollary is that all people (at least all sane adults) have one vote in the political process.
Legal justice, sometimes referred to as criminal justice, connotes justice between people and the law. This sphere of justice encompasses civil, criminal, and commercial law. Due process – the right to equal treatment at and before the law – is a vital component of legal justice.
Distributive justice denotes the fair allocation of power, economic resources, and other goods. A major challenge with respect to distributive justice is balancing the tension between respect for private property and the need to ameliorate existing injustice. The principles of distributive and commutative justice together argue for democracy as the form of government most consistent with Christianity.
The three spheres of justice constitute a useful framework for examining the different areas of life in which justice is important. However, the spheres require further principles before they have sufficient specificity to define a Christian ethic, e.g., the biblical teaching that all people are worthy of equal dignity and respect because God created all.
Alternatively, in the latter half of the twentieth century, Christians sometimes speak more about rights than about justice. The concept of rights is not an explicitly biblical concept. However, noted Yale philosopher Nicholas Wolterstorff, writing from an avowedly Christian perspective, argues that the secular concept of human rights actually emerged out of the secularization of the Christian tradition (Justice: Rights and Wrongs, (Princeton, NJ: Princeton University Press, 2008)).