Attention returning to its source.
Most of the time, via the senses, via perception, thinking, sensing, feeling, emoting, attention is focused on the content of experience. The experience is objective, material and personal made out of subjects and objects.
In order for attention to turn itself onto its source, like a snail retreating into its shell, attention needs to turn itself away from the objects and look at the looking itself. It has to defocus and delocalize, as if dissolving into itself, falling back into itself, where only silence resides without any objects.
The mind cannot find anything to hold on to as there are no objects for it to move towards.
In looking for its source, the mind empties itself of objects and halts its outward movement. This provides an opportunity for the presence of awareness to be noticed.
In time, we realize that this noticing is an inherent quality of aware presence and not a personal quality.
Upon this return, we find presence, awareness standing on its own. There is no one or nothing outside of presence/awareness. It is presence/awareness being face to face with itself without any intermediary.
One could say, mind is present to itself as presence/awareness.
Jean Klein used to say (paraphrasing): it is an absence without anyone being present or absent to this absence.
The peace of being.