‘On Cleaving to God’ ~ Attributed to Saint Albert the Great (Albertus Magnus); Chapters 4 & 5; pages 5-8

[Saint Albert the Great – Albertus Magnus – XIII Century AD; Duchy of Bavaria/Cologne, Holy Roman Empire; (Aged ca 80); German Dominican friar, philosopher, scientist, and bishop; one of the greatest medieval philosophers and thinkers; Doctor of the Church]
“Chapter IV ~ How man's activity should be purely in the intellect and not in the senses
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 imply, 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.
For this is the end of all spiritual exercises - to turn the mind to the Lord God and rest in him with a completely …More

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In Principio shares this

"After all, purity of heart is recognized as the most important thing among all spiritual practices, as its final aim, and the reward for all the labors that a spiritual-minded person and true religious may undertake in this life. For this reason you should with all care, intelligence and effort free your heart, senses and desires from everything that can hinder their liberty, and above all from everything in the world that could possibly bind and overcome you."

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"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 imply, 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."