From Weavings Newsletter April 2011
The nature of the soul is aptly compared to a very fine feather or very light wing. If it has not been damaged or spoiled by any moisture falling on it, it is borne aloft almost naturally to the heights of heaven by the lightness of its nature and the aid of the slightest breath. But if it is weighted by any moisture falling upon it and penetrating it, it will not only not be carried away by its natural lightness into any aerial flights but will actually be dragged down to the depths of earth by the weight of the moisture it has received.
So also the soul, if it is not weighted with faults that touch it and the cares of this world or damaged by the moisture of injurious lusts, will be raised by the natural blessing of its own purity and borne aloft to the heights by the light breath of spiritual meditation. Leaving things low and earthly, it will be transported to those that are heavenly and invisible.
So we are well warned by the Lord's command: "Be on your guard so that your hearts are not weighed down with dissipation and drunkeness and the worries of this life." If we want our prayers to reach not only the sky but what is beyond the sky, let us be careful to reduce the soul, purged from all earthly faults and purified from every strain, to its natural lightness. Then our prayers may rise to God unchecked by the weight of any sin.
Cassian uses the image of feathers to describe the soul in prayer. What images of prayer and the soul are meaningful to you?
 John Cassian, Making Life a Prayer: Selected Writings of John Cassian, ed. Keith Beasley-Topliffe, Upper Room Spiritual Classics, (Nashville: Upper Room Books), 49.