Researchers note a slight influence of Aristotle’s "Nicomachean Ethics" in Antiquity and considerable influence in the Middle Ages, which has resulted in numerous Byzantine and scholastical commentaries on the treatise. How the Christian and pagan ethics were combined in the Middle Ages? Apparently, as in the case with the logic, theologians borrowed the categorical apparatus of Greek philosophy from the ancient culture.
Aristotle applies the doctrine of the categories to resolve specific issues of ethics. Having remembered the ten categories of Aristotle, it is possible to compare them with the ten Commandments given by God to Moses. What is similar in them, except the quantity of 10? Immediately you will notice the exceptional value of the first category (the essence) and, accordingly, the first commandment (I am Being, or, in another translation, I am that I am). The rest of the nine categories, as well as the nine Commandments, do not have a sense without the first one, they are only the properties or the conclusions of it. Ten
categories of Aristotle were later reduced to two basic ones: substance and accidence. Ten Commandments of Moses are reduced in the New Testament to two main ones: "You shall love the Lord your God with all your heart, with all your soul, with all your strength, and with all your mind; and your neighbor as yourself" (Lk 10:27).
Many associations are arising during the comparison of the other categories and commandments.
Comparison of the table of categories and commandments lets us understand why medieval theologians, which have developed the Christian ethics that arised from the ancient ethics of Old Testament could not do without the categorical apparatus of ancient philosophy, without the ability to use the mind for achieving the happiness (blissness). Aristotle emphasized this so important virtue in his "Nicomachean Ethics" as a so-called dianoethic (reasonable) virtue.