Consider that we are in the midst of a vast ocean, a sea of many levels and frequencies. Some are seen and some are not. Like an ocean which may have salt layers in different concentrations, impurities dissipated in some others, water flowing in internal rivers, fresh water interspersed, and an oil slick on top; this ocean we are in has many different progressively refined intertwined and emmeshed layers.
Consider also that this ocean is alive in function and aware in consciousness. Add to that, that it is "pressing upon" everything within it, trying to move through all forms. This is much like an ocean which presses upon the dikes or rocks that are barriers to its movement - only this ocean is not different than those rock, the sand, or even the waves.
The natural course of the water is to penetrate anything with an opening, and to flow into any recess. So too with the teachings. It also flows into and through the openings and presses upon that which it contacts. As weaknesses develop or the resistance thins, its presence can be more strongly felt. In other words, the teaching is always pressing to express itself through whatever channel is available. It flows according to the size of the "pipe" and the coarseness of the filter or screen over the opening. The finer the mesh the more it allows through the more refined, with less coarse parts not able to filter through. Such is the overall progress and movement of the teaching. It is into the consciousness of the receptacle that it flows; and through the filter of the mind, breath, and heart it is refined.
The teaching thus continues in all ages and in all ways available to it, taking on the characteristics of the vessels through which it flows. From time to time there are vessels which open more than others and are able to focus and attune to the higher levels of the "sea". These become the seers. At other times, some of those people go further and actually bring a part of the teaching through them. They become the guides, or teachers. They are able to maintain an opening or channel through which the teaching can flow. As they become more used to working in that capacity they are able to widen the pipe or transmission line and allow more to flow through it. Their capacity increases. As they refine and eliminate the filters of smaller personality, together with its desires, the teaching flows clearer, with less to taint of color it. Eventually it flows unimpeded, through the person who then becomes part of it. As this process happens there is also a corresponding change of point of view. So instead of looking, seeing, or experiencing from the perspective of the observed person it moves toward that of the teaching and its source. In other words, "I" becomes more inclusive, connected, and a single active unit - through which it uses the focus, enlarged body, personality, and mind as a tool for expression.
This person then becomes the personification of the teaching. And through him or her,the expression can be tailored to the needs of those with whom it comes in contact. That person also establishes a connection to the teaching which can flow from him or her to the next vessel, or person. The recipient is usually call a student. The teacher, more properly in function "the guide", being the one through which the Spirit of Guidance flows. That one is also able to make another more direct connection between the student and the teaching. This expandable pipe or tube is established through the process of initiation. It is filtered and tempered by the degree of universality or provincialism in which it is structured. Eventually, through time, practice, and attunement of heart and breath, the student becomes aware of both the source of the flow through the teacher, and the other teachers in the "pipeline" through which it comes; and also the direct link or pipe to the guidance through his or her own expanding "pipe" of and within the Divine Heart. Both of these act in concert.
The teaching is brought through the person of the so-called teacher, and is also tailored to the audience, be that the group or individuals. The primary point is that whatever is given is appropriate at the time. It is enough, and most satisfactory to provide the student(s) with that which they can use to take the next step. More than that is not needed other than to lay the foundation or framework for future steps. This is determined by the needs and potentials of the people and situation. The key here is to do what is appropriate, at the right time, with the correct people or person, in the right way.
That teaching then can take any of many forms. The only one process that eventually must be included is the transference through heart and breath. All others either lead up to that, reinforce it, or are for other purposes. The teaching can take the form of lectures, meetings, practices, lessons, writings, service, or nothing at all. It can be silent or aloud. The method is not so important as is the conveyance or transmission; which can then unfold within the student and be applied by that person through his or her own life. The means to open the way for that transmission then is the outer more recognizable work or "teaching", but the more real one is the underlying and overshadowing communication through Heart and Breath of the Universal Spirit of Guidance.