According to Cicero, the sources of moral righteousness are four in number (De Officiis I.15):
1. The perception and intelligent development of truth (In perspicientia veri sollertiaque versatur);
2. The preservation of civil society, with the faithful rendering to everyone what he is properly owed (In hominum societate tuenda tribuendoque suum cuique et rerum contractarum fide);
3. The greatness and power of a noble and unconquerable spirit (In animi excelsi atque invicti magnitudine ac robore);
4. In the order and moderation of things which consist of temperance and self-control (In omnium, quae fiunt quaeque dicuntur, ordine et modo, in quo inest modestia et temperantia).
What is moral and good, according to Cicero, has to spring from one or more of these sources. They can be connected with each other, depending on the situation. The first of these sources, as listed above, revolves around the search for truth. The remaining three relate to our conduct within organized society.
And this is where Cicero makes an important point. The search for truth is a morally righteous thing.
Truth is not primarily an intellectual pursuit; it is a moral one. It is an impulse that arises from the deepest core of our moral being.