Summum bonum

Summum bonum is a Latin expression meaning "the highest good", which was introduced by Cicero, to correspond to the Idea of the Good in ancient Greek philosophy. The summum bonum is generally thought of as being an end in itself, and at the same time containing all other goods. The term was used in medieval philosophy and in Kantianism, to describe the ultimate importance, the singular and overriding end which human beings ought to pursue. In the Thomist synthesis of Aristotelianism and Christianity, the highest good is usually defined as the life of the righteous and/or the life led in communion with God and according to God's precepts.

Plato's The Republic argued that, “In the world of knowledge the idea of good appears last of all, and is seen...to be the universal author of all things beautiful and right”. Silent contemplation was the route to appreciation of the Idea of the Good.

Aristotle in his Nichomachean Ethics accepted that the target of human activity, “Must be the 'Good', that is, the supreme good.”, but challenged Plato's Idea of the Good with the pragmatic question: “Will one who has had a vision of the Idea itself become thereby a better doctor or general?”. However, arguably at least, Aristotle's concept of the unmoved mover owed much to Plato's Idea of the Good.

Philo of Alexandria conflated the Old Testament God with the unmoved mover and the Idea of the Good.Plotinus, the neoplatonic philosopher, built on Plato's Good for his concept of the supreme One, while Plutarch drew on Zoroastrianism to develop his eternal principle of good.

...
Wikipedia