It is useful and orienting to distinguish between two types of prayer – apophatic prayer, which is prayer without words and images, and kataphatic prayer, which is prayer using words and images, whether spoken and manifested or unspoken and interior. Most devotional practices fall naturally in the kataphatic class, as this is the way for most people, and indeed, it is easier to feel love, reverence and devotion to some representation of God or an avatar to those natively  inclined to reside in their hearts than to a nameless, ineffable “nothing.” As in mainstream Christianity, the Bhakti yoga of Hinduism is oriented along kataphatic lines. Kataphatic prayers include what we would all consider prayer when we naturally think of the term – a conversation with God, expressing feelings and freely using concepts in a linguistic-based interaction to a “Thou” beyond us. The Lord’s prayer is an example.

Apophatic prayer is a different class of prayer, one that is more suited to those whose intuitions of God are impersonal, and/or whose approaches to the Divine may be less emotionally centered. Apophatic prayer, as mentioned previously, dispenses with the use of words or images, or sometimes, uses them only instrumentally, in a de minimus manner. The wordless intent and feeling-value of the prayer, along with the sense of Presence this might invoke, is the primary focus and objective of this class of prayer. One of the Christian masterpieces on this point is the 14^th century mystic work “The Cloud of Unknowing”, author unknown. The entire book is worth reading from cover to cover, as it addresses many aspects of mystical prayer in language that is accessible and personal to this day (I recommend the Johnston translation [1973]).

To give you a flavor of The Cloud of Unknowing, here is an introductory excerpt , which lays out the general approach and devotional attitude to this form of contemplative prayer:

How the work of contemplation shall be done; of its excellence over all other works.
This is what you are to do: lift your heart up to the Lord, with a gentle stirring of love desiring him for his own sake and not for his gifts. Center all your attention and desire on him and let this be the sole concern of your mind and heart. Do all in your power to forget everything else, keeping your thoughts and desires free from involvement with any of God’s creatures or their affairs whether in general or in particular. Perhaps this will seem like an irresponsible attitude, but I tell you, let them all be; pay no attention to them.
What I am describing here is the contemplative work of the spirit. It is this which gives God the greatest delight. For when you fix your love on him, forgetting all else, the saints and angels rejoice and hasten to assist you in every way—though the devils will rage and ceaselessly conspire to thwart you. Your fellow men are marvelously enriched by this work of yours, even if you may not fully understand how; the souls in purgatory are touched, for their suffering is eased by the effects of this work; and, of course, your own spirit is purified and strengthened by this contemplative work more than by all others put together. Yet for all this, when God’s grace arouses you to enthusiasm, it becomes the lightest sort of work there is and one most willingly done. Without his grace, however, it is very difficult and almost, I should say, quite beyond you.
And so diligently persevere until you feel joy in it. For in the beginning it is usual to feel nothing but a kind of darkness about your mind, or as it were, a cloud of unknowing. You will seem to know nothing and to feel nothing except a naked intent toward God in the depths of your being [Ed: Emphasis added]. Try as you might, this darkness and this cloud will remain between you and your God. You will feel frustrated, for your mind will be unable to grasp him, and your heart will not relish the delight of his love. But learn to be at home in this darkness. Return to it as often as you can, letting your spirit cry out to him whom you love. For if, in this life, you hope to feel and see God as he is in himself it must be within this darkness and this cloud. But if you strive to fix your love on him forgetting all else, which is the work of contemplation I have urged you to begin, I am confident that God in his goodness will bring you to a deep experience of himself.

Chapter 3, The Cloud of Unknowing, Editor: WIlliam Johnstone 1973

One-syllable prayer

as presented in the Cloud of Unknowing

The Cloud of Unknowing speaks eloquently in multiple places, distinguishing between Martha’s way (active engagement) and Mary’s way (contemplative engagement) in the prayer life, and exploring different aspects of the one-syllable prayer:

Chapters 37-38:
37. […]Contemplatives rarely pray in words, but if they do, their words are few. The fewer the better, as a matter of fact: yes, and a word of one syllable is more suited to the spiritual nature of this work than longer ones. For now the contemplative must hold himself continually poised and alert at the highest and most sovereign point of the spirit[…]we can understand the efficacy of one little interior word, not merely spoken or thought, but surging up from the depths of a man’s spirit, the expression of his whole being…And so this simple prayer bursting from the depths of your spirit touches the heart of Almighty God more certainly than some long psalm mumbled mindlessly under your breath. This is the meaning of that saying in Scripture: “A short prayer pierces the heavens.”

38. Why do you suppose that this little prayer of one syllable is powerful enough to pierce the heavens? Well, it is because it is the prayer of the man’s whole being. A man who prays like this prays with all height and depth and length and breadth of his spirit. His prayer is high, for he prays in the full power of his spirit; it is deep, for he has gathered all of his understanding into this word; it is long, for if this feeling could endure, he would go on crying out forever as he does now; it is wide, because with universal concern, he desires for everyone what he desires for himself.…

A key point that can be helpful to remember here is that this prayer is intended to be an exhortation, a relentless and insistent pounding/crying for attention from the Most High in the nakedness of one’s being. As such, it is best not to dilute the forcefulness of the intent with extraneous sounds and elaborating meanings. Think of crying for help and a clarifying Presence on the topic selected. Many of the same sacred words presented in the page on Centering Prayer can be taken for use in this practice, keeping in mind that even two-syllable words like “Jesus” or “Amen” do not technically meet the requirements of this ‘cry in the wilderness’ type of prayer. The following is that list reproduced, culled for multi-syllabic words, and modified with additions:

• Come,
• Help,
• Still,
• Faith,
• Grace,
• God,
• Love,
• Peace,
• Lord