One Love To Rule Them All:

The medieval world was therefore part of a multifaceted and hierarchical universe in which all elements were bound together in a “great chain of being.” The force which bound all these elements together was love, also called caritas or charity, what St. Augustine (354-430 A.D.) called the whole motion of the soul towards God for His sake and towards one’s self and one’s fellow man for the sake of God. All of scripture, indeed all of Christian doctrine, taught the essential importance of charity in this spiritualized sense.