It follows, then, that tefilah is a concise summary of "I have set G‑d before me at all times" (Psalms 16:8). It is a synonym for kavanah, for these two concepts are in effect one and the same.

Kavanah means proper thoughts and devotion, proper intention and attention, "to clear the heart (mind) of all thoughts and visualize oneself as standing in the presence of the Shechinah."

Practically speaking, this means that prayer involves two faculties of man: speech and thought.

When there is a lack of kavanah, a lack of awareness of the fundamental principle that tefilah means 'standing before the Al-mighty and addressing Him,' there is in effect no prayer.

The articulation of the words of prayer and the accompanying thought are like the body and soul of prayer, and tefilah without kavanah is "like a body without a soul, a husk without a kernel" of which it is said, "This people draws near, with its mouth and lips it honors Me, but it has removed its heart from Me" (Isaiah 29:13).

When praying like this, one may as well be digging holes in the ground or chopping wood in a forest. That kind of prayer is no different than the mindless chirping of birds.

The significance of kavanah, the fact that consciousness is the essence of tefilah, lends validity and value to the prayers of the simple and ignorant.

They may not understand the meanings of the words they utter, but insofar that their prayers are offered with simple faith and total sincerity they are beloved and acceptable.

Indeed, the pure prayer of simple folks is favored by G‑d even when read incorrectly or naively mistaking its true meanings, or when altogether spontaneous as opposed to the prescribed formulations of the prayer-book.

Nonetheless, notwithstanding the fact that kavanah is the very soul of prayer, this does not mean that it could be offered as a mental exercise alone.

Whenever possible, it must be articulated.

It must be expressed by spoken words. For speech - which is an extension and manifestation of thought - is the unique mark of the human.

Generally speaking, then, the absence of speech means absence of full human status. In that defective state one is no longer a human recipient for the Divine grace. Thus one must articulate requests with actual words - requesting as a human being who has needs and who is able to have these needs filled.

The need for verbal prayer is understood also by a more literal aspect of the speech-thought/body-soul analogy, viewing the body as a vessel or container: verbal prayer provides a 'vessel' or 'container' to receive the outpouring of the Divine grace requested.

Speech has a physical reality and makes it possible for the Divine grace to flow to the physical reality of the material world.

The spoken words thus become the instrument or intermediary through which the spiritual fulfillment of prayer can become realized on the physical level.

Thought, on the other hand, is a mental or spiritual reality. It is a mental or spiritual tool or vessel. To be sure, mental prayer, too, is 'heard' Above, and it, too, draws forth a response. The answer to prayer, however, is restricted to the vessel provided; thus it will flow only to the spiritual vessel of thought, and will not become realized on a physical level.