I have had the idea of writing something for myself on and about the state of complete and full abstraction from everything and of cleaving freely, confidently, nakedly and firmly to God alone, so as to describe it fully (in so far as it is possible in this abode of exile and pilgrimage), especially since the goal of Christian perfection is the love by which we cleave to God.
In fact everyone is obligated, to this loving cleaving to God as necessary for salvation, in the form of observing the commandments and conforming to the divine will, and the observation of the commandments excludes everything that is contrary to the nature and habit of love, including mortal sin.
Members of religious orders have committed themselves in addition to evangelical perfection, and to the things that constitute a voluntary and counselled perfection by means of which one may arrive more quickly to the supreme goal which is God.
The observation of these additional commitments excludes as well the things that hinder the working and fervour of love, and without which one can come to God, and these include the renunciation of all things, of both body and mind, exactly as one’s vow of profession entails.
Since indeed the Lord God is Spirit, and those who worship him must worship in spirit and in truth, in other words, by knowledge and love, that is, understanding and desire, stripped of all images.
This is what is referred to in Matthew 6.6, ‘When you pray, enter into your inner chamber,’ that is, your inner heart, ‘and having closed the door,’ that is of your senses, and there with a pure heart and a clear conscience, and with faith unfeigned, ‘pray to your Father,’ in spirit and in truth, ‘in secret.’
This can be done best when a man is disengaged and removed from everything else, and completely recollected within himself. There, in the presence of Jesus Christ, with everything, in general and individually, excluded and wiped out, the mind alone turns in security confidently to the Lord its God with its desire.
In this way it pours itself forth into him in full sincerity with its whole heart and the yearning of its love, in the most inward part of all its faculties, and is plunged, enlarged, set on fire and dissolved into him.
Albert the Great (1193/1206–1280) [attributed]: On Cleaving to God, 1.