Now the more the mind is concerned about thinking and dealing with what is merely lower and human, the more it is separated from the experience in the intimacy of devotion of what is higher and heavenly;
while the more fervently the memory, desire and intellect is withdrawn from what is below to what is above, the more perfect will be our prayer, and the purer our contemplation, since the two directions of our interest cannot both be perfect at the same time, being as different as light and darkness.
He who cleaves to God is indeed translated into the light, while he who clings to the world is in the dark.
So the supreme perfection of man in this life is to be so united to God that all his soul with all its faculties and powers are so gathered into the Lord God that he becomes one spirit with him, and remembers nothing except God, is aware of and recognises nothing but God, but with all his desires unified by the joy of love, he rests contentedly in the enjoyment of his Maker alone.
Now the image of God as found in the soul consists of these three faculties, namely reason, memory and will, and so long as they are not completely stamped with God, the soul is not yet deiform in accordance with the initial creation of the soul. For the true pattern of the soul is God, with whom it must be imprinted, like wax with a seal, and carry the mark of his impress.
But this can never be complete until the intellect is perfectly illuminated, according to its capacity, with the knowledge of God, who is perfect truth, until the will is perfectly focused on the love of the perfect good, and until the memory is fully absorbed in turning to and enjoying eternal happiness, and in gladly and contentedly resting in it.
And since the glory of the beatitude which is achieved in our heavenly homeland consists in the complete fulfilment of these three faculties, it follows that perfect initiation of them is perfection in this life.
Happy therefore is the person who by continual removal of fantasies and images, by turning within, and raising the mind to God, finally manages to dispense with the products of the imagination, and by so doing works within, nakedly and simply, and with a pure understanding and will, on the simplest of all objects, God.
So eliminate from your mind all fantasies, objects, images and shapes of all things other than God, so that, with just naked understanding, intent and will, your practice will be concerned with God himself within you.
Albert the Great (1193/1206–1280) [attributed]: On Cleaving to God, 3 & 4.