“So, from primordial time, all that is ultimately consumed within the exalted dimensions, types of pristine awareness, qualities, and enlightened activities abides within the essence of the tathgatas. When someone becomes a Buddha, these are not then newly acquired but are merely separated from the defilements that have eclipsed them.”
[From The Essence of Zhentong by Jetsun Taranatha]
In other words, according to this teaching the innate quality of your mind is ultimate clarity, or Awakeness. However, for most of us this Awakeness is obstructed by habitual patterns, conditioning, and various forms of obscuration. This situation has been likened to a mirror covered in dust and grime. The mirror is there beneath the dust. Wipe the dust away, and the mirror will shine forth.
According to this teaching, buddha-nature is not something you presently lack, and can later acquire. Buddha-nature is something you already have, it is the very essence of your mind. The difference between ordinary beings and fully enlightened buddhas is that the latter have removed the obstructions that prevent this Awakeness from shining forth. This is a task of Dharma practice, to remove the obstructions and obscurations. There are innumerable methods available for doing this, applicable to beings of different capacities and dispositions.
OM AH HUM
Dolpopa Sherab Gyaltsen
This has been on my wish list for a while now. Published in 2006, this is the first English translation of Dolpopa Sherab Gyaltsen’s masterpiece titled Mountain Doctrine wherein he gives precise teachings on the rangtong (self-emptiness) and zhentong (other-emptiness) views. I am currently re-reading The Buddha from Dolpo by Cyrus Stearns, which is excellent–both in offering a basic biography of Dolpopa as well as providing many of his arguments regarding Buddhanature and other teachings. Dolpopa was also a master of Kalachakra tantra, and is recognized as such even to this day by many of the Vajrayana lineages (not just the Jonang).
For those who are interested in Buddhadharma but have never heard about Dolpopa, I recommend checking him out (probably starting with The Buddha from Dolpo). Hopefully we will see more from Dolpopa in English, as his collected works are gaining attention in academia.
Other related books of interest:
The Buddha from Dolpo (by Cyrus Stearns)
The Essence of Other-Emptiness (by Jetsun Taranatha. Translated by Jeffrey Hopkins)
The Kalachakra Tantra: The Chapter on Sadhana Together with the Vimalaprabha Commentary (translated by Vesna A. Wallace)
Introduction to the Kalachakra Initiation (by Alexander Berzin)
Ornament of Stainless Light (translated by Gavin Kilty)