Though love is not itself a movement of the appetite towards an object, it is a change the appetite undergoes rendering an object agreeable. Love unites by making what is loved as agreeable to the lover as if it were himself or a part of himself. Clearly then, as a change induced in us by an agent, love is a passion: the affective emotion strictly so, the will to love by stretching of the term. The first change the object produces in our appetite is a feeling of its agreeableness: we call this love (weight can be thought of as a sort of natural love) then desire moves us to seek the object and pleasure comes to rest in it.

Whatever we desire acts on us in this way, first arousing an emotional attachment to itself and making itself agreeable, and then drawing us to seek it. By passion we mean some result of being acted on: either a form induced by the agent (like weight) or a movement consequent on the form (like falling to the ground).

Not only our so-called natural ability to grow and propagate exemplify natural love, but every faculty has a built-in affinity for what accords with its nature. “The emotion of love is an affective emotion, directly reacting to goodness, rather than an aggressive one, reacting to challenge. So when the scriptures ascribe dimensions to God they are using spatial extension to symbolize the extent of God's power just as they ascribe bodily organs to God as metaphors for their functions, and postures like sitting or standing to symbolize authority or strength.” The most excellent existent of all then cannot be a body. Thirdly, living bodies are superior to other bodies and what makes a body living is not the dimensions which make it a body (for then everything with dimensions would be living), but something more excellent like a soul. But the starting-point for all existence must be wholly real and not potential in any way: though things that get realized begin as potential, preceding them is the source of their realization which must already be real. Secondly, things with dimensions are potential of division. Firstly, no body can cause change without itself being changed. God is spirit, without bodily dimensions. “God is not, like creatures, made up of parts.

St thomas summa