This document outlines principles of friendship according to various religious texts and philosophers. It discusses how friendship is built on qualities like frequency of interaction, authenticity, maturity, sympathy, humility, honesty, confidentiality, and having a shared purpose. True friendship involves mutual trust, respect, affection, knowing each other's faults, offering help in times of need, spurring each other to goodness, and maintaining discretion with private matters. Famous quotes are provided, such as Aristotle's definition of a friend as "a single soul dwelling in two bodies."