As surprising as it might sound, beauty lies at the heart of motive. Why we do what we do is a question of desire, and desire is rooted in what we think is good and beautiful.
Jonathan Edwards tackled the questions of motive, desire, and freedom in his work The Freedom of the Will. There Edwards argued that the strongest inclination is the choice one makes, and that choice is the same as the will. There is no neutral “deciding faculty” within us, independent of beauty. Whatever the mind perceives as the greatest apparent good, the heart chooses.
In Edwards’ view, the human will is not the faculty that decides, it is the decision itself. The mind knows the objects of desire, and the heart chooses, or loves what it desires as the greatest good. The greatest motive always prevails as the thing chosen. In other words, what the will chooses is precisely what it loves. This is why it is not strictly correct to speak of “choosing to love”, for one is really thereby saying “choosing to choose” or “loving so as to love”.
The will does not choose to love; the will chooses what it loves. Your chosen desires reflect what you think it best to choose. Loves can be formed and shaped, but they cannot simply be willed into being. You always love what you think is most beautiful; or to put it differently, best.
Lying at the heart of human action is then a picture of beauty: what the good life is, what is most pleasurable valuable, reliable. Every one of us is inclined towards a vision of something we believe is good. J. K. A. Smith writes, “Our ultimate love is oriented by and to a picture of what we think it looks like for us to live well, and that picture then governs, shapes, and motivates our decisions and actions.” This picture is not a set of abstract ideas, as much as it is an aesthetic idea, an affective, sensible picture of what reality is really like or should be like. This is the telos to which the human heart is inclined; it is its treasure, to which you will always find the heart inclined (Matt. 6:21).
Here is another reason why beauty and morality are intertwined. Those who are hardened sinners do not only do what is evil, they “also approve of those who practice them.” (Rom. 1:32) That is, they delight in sin. They “love darkness, because their deeds are evil” (John 3:19), and they “take pleasure in unrighteousness (2 Thes 2:12). For them, their sin is beautiful. Evil is aesthetically pleasing to them. Wickedness is something to be gazed at, admired, courted, pursued, coveted, memorialised, shared, and celebrated. When you love or desire what God hates, then what is ugly to God has become beautiful to you, and what is beautiful to God has become ugly to you. You have inverted good and evil, beauty and ugliness (Is. 5:20).
If what motivates you is something God condemns, you are doubly condemned: you commit acts of evil, and you do so because you treasure what God abhors. On the other hand, if your heart finds joy and delight in holiness, you will pursue those things, and find joy in them. A background vision of God’s holiness, harmony and happiness will explain what a holy man pursues and why.