What performances of our repertoire are met with the approbation of those peers we desire approbation from? Those become the beliefs that we hold within our breasts and that we judge ourselves upon.
It is because we desire the connection with others that we adopt through interaction beliefs that bring us approbation.
This is a trait peculiar to humans among the animal kingdom. (This is all in Adam Smith's "Theory of Moral Sentiments.")
It is also a practice that we see God performing: "This is my beloved Son in whom I am well pleased, listen to Him."
The peculiar thing about Christianity is that we can understand ourselves to be performing a radical and redemptive repertoire before people who will be challenged by it, and in many cases meet our performance with disapprobation, but we go on because the Holy Spirit in us overcomes our need for the approbation of people.
In a way, Christianity is sociopathic, or others have called it atheistic toward civil religion or social morality.