Summarised by John D. Hughes from the book 'Flavour of Dhamma' by Phra Acharn Thate
The Heart is the forerunner of all things
The Heart is their chief
Attainment is via the Heart.
In its true state the "heart" is a completely neutral blank state. When this state breaks up and outward expressions of the heart (eg. happiness and sadness, love and hatred) display themselves, this is the "Citta". It could be said that the heart is a state of rest and the "Citta" is a state of action or work - the passive and active sides of NAMADHAMMA.
Whoever maintains Sila because he thinks he is forced to, will suffer and sin because he keeps Sila in vain. When we keep Sila of any sort, our hearts are uneasy and hesitant - fearing that they will not be able to perform the bad Kamma that they have done previously and will do again later on. The reason for this is that we have submitted our Cittas to the command of the Kilesas.
Upon having Sila one shall then practice Dhamma to higher levels - climbing up by degrees. If one were to call our body-hearts a cabinet of Dhamma this would not be incorrect.
The four Satipatthana are Lokuttara Dhamma: Kayanupassana, Vedananupassana, Cittanupassana and Dhammanupassana. Whichever world, Dhamma is that; Whatever Dhamma, the World is that. Satipatthana is the place to establish and train the SATI (mindfulness). Lord Buddha taught that one should see the Dukkha of Sati not stopping and staying in one place.
That Sati which still goes following the knowing of various things will never have a day to catch them up - not at all. When Sati and knowledge abide together in the Citta it must stop and be still - being one.
The four Satipatthana are LOKUTTARA Dhamma, therefore, the practitioner should be someone who has already seen the ill-effects of LOKIYA or the five forms of sensual experience - the enemies of Satipatthana. Do not hope or want for anything.
Any hoping or wanting will be an obstacle to progress in Satipatthana. The attitude of Sati should simply be one of watching over the Citta, making it stay in the present.
Then the Citta gazes at the object and does not withdraw, even for a short time, the object will vanish in a flash. When Sati has no object to focus on it will vanish simultaneously and the Citta and the object will combine to become just the Citta. This has similar characteristics to someone asleep but it is not sleep as there is still a certain peculiar awareness.
One does not know where one is, who one is or what one is doing but one does have some basic awareness. This is called EKAGGATACITTA. Other aspects of Satipatthana are of the same manner. When one withdraws to the state that one was in initially this state is more splendid because we will see what is behind objects and we will see and understand the conditions of reality. When the work is successful the Citta will take a rest... unintentional visions and NIMITTAS may also arise.
When one places one's Sati on Vedana, the CITTA will release its initial attachments and assumptions.
When one has established SATI on the CITTA one should just gaze passively at it. SATI and CITTA will become one and the same; this is EKAGGATARAMMANA.
When the CITTA has trained until it is experienced and clever it will be comprised of PANNA and will be able to use KAMA objects in a way that does not give rise to KAMAKILESA.
Someone who is forgetful and can hardly remember a thing is called someone whose SATI is not good. Someone who has no SATI is considered intellectually delirious.
In a second method Vedana is inspected. When one examines, the CITTA will stop being jumbled and will be concentrated on VEDANA. Then let SATI become firmly established on the CITTA and investigate the CITTA as being ANATTA. The Citta and Sati will combine together at the same place. When the CITTA examines and knows in this manner it will become more subtle, by degrees.
Then establish Sati on DHAMMA. Recall no essence can be found, they are ANATTA; they make the one who clings to them suffer in vain. It is the DHAMMARAMMANA that arise via the six Ayatana which the Citta grasps, taking them to be a self. To give a simile, it is like an iron striking against a stone thus giving rise to a spark, which flashes momentarily then dies out.
Someone who likes and is attached to these objects wants to get and wants to see those sparks so he takes the iron and strikes it against the stone again.
SANNA, recognition of those various objects is ANATTA. When Sati is set steadfastly on Dhamma, the Citta will be far from delusion. It will see that DHAMMA RAMMANA, SANNA and SANKARA are simply SABHAVA DHAMMAS - (natural phenomena).
In the end the DHAMMARAMMANA of Sati will disappear in a flash, thus becoming EKAGGATACITTA.
The language of the heart known by oneself is very difficult to express clearly in ordinary language.
The Citta works to perfection in the 4 ARIYA SACCA, then it comes together, being enlightened in a single Citta moment. Therefore enlightenment is enlightenment in a heart that is clean, clear and pure.
Knowledge that is called NEYYADHAMMA is knowledge that arises from pure Citta and has SAMMASAMADHI as its origin.