It is an impossibility for him who, overcome in the matter of a small possession, has once admitted into his heart a root of evil desire, not to be i… - John Cassian

But they alone see his Godhead with purest eyes who,
mounting from humble and earthly tasks and thoughts,
go off with him to the lofty mountain of the desert which,
free from the uproar of every earthly thought and disturbance,
removed from every taint of vice,
and exalted with the purest faith and with soaring virtue,
reveals the glory of his face and the image of his brightness to those who deserve to look upon him with the clean gaze of the soul.

This will be the case when every love, every desire, every effort, every undertaking, every thought of ours, everything that we live, that we speak, that we breathe, will be God, and when that unity which the Father now has with the Son and which the Son has with the Father will be carried over into our understanding and our mind, so that, just as he loves us with a sincere and pure and indissoluble love, we too may be joined to him with a perpetual and inseparable love and so united with him that whatever we breathe, whatever we understand, whatever we speak, may be God.
In him we shall attain, I say, to that end of which we spoke before, which the Lord longed to be fulfilled in us when he prayed: ‘That all may be one as we are one, I in them and you in me, that they themselves may also be made perfect in unity.’ (John 17:22-23)

Not without reason has this verse [Psalms 70:1] been selected from out of the whole body of Scripture. ... ‘O God, incline unto my aid.’ ... This verse should be poured out in unceasing prayer so that we may be delivered in adversity and preserved and not puffed up in prosperity. You should, I say, meditate constantly on this verse in your heart. You should not stop repeating it when you are doing any kind of work or performing some service or are on a journey. Meditate on it while sleeping and eating and attending to the least needs of nature. This heart’s reflection, having become a saving formula for you, will not only preserve you unharmed from every attack of the demons but will also purge you of every vice and earthly taint, lead you to the theoria of invisible and heavenly realities, and raise you to that ineffably ardent prayer which is experienced by very few. Let sleep overtake you as you meditate upon this verse until you are formed by having used it ceaselessly and are in the habit of repeating it even while asleep.