Earlier I suggested AN5.28 could be the original source of the jhana similes in the Pali. There are two other similarities between this sutta and the Pali Kayagatasati Sutta (MN119):
- The suttas both have the same three similes for “realising any state that may be realised”, in identical order and wording.
- They mention six identical benefits, in exact same order, although with slightly different wording.
The suttas mention the following similes (apart from the jhana similes):
MN119 & MA81 (Kayagatasati Suttas)
Similes for “included within himself whatever wholesome states”:
- ocean
Similes for “Māra finds an opportunity”:
- heavy ball thrown at clay
- dry wood
- empty jug
Similes for “Māra finds no opportunity”:
- light ball thrown at door
- wet wood
- full jug
MN119 & AN5.28 (not MA81!)
Similes for “realising any state that may be realised”:
- full jug
- full pond
- readied chariot
The suttas mention the following benefits:
MN119 & MA81 (benefits of kayagatasati)
- conquer of discontent and delight
- conquer of fear and dread
- bear cold and heat
- the four jhānas
MN119 & MA81 (benefits of kayagatasati) and AN5.28 (benefits of samadhi)
- supernormal powers
- divine ear
- mind reading
- past life recollection
- divine eye
- enlightenment
The three similes for “realising any state” are found as a set only in MN119 & AN5.28 (in the Pali Canon at least). This strongly suggests a connection between the two texts. As some scholars have said, it isn’t rare for a reciter to have stringed together the otherwise unconnected passages by mere similarity or identical key words (e.g. “kāya”), whether intentionally or by mistake.
But what makes the connection even more certain, is that the Chinese Kayagatasati Sutta (MA81) does not have the three similes! Even though it has all the other seven similes of MN119 (ocean, heavy ball, etc). So these three similes seem to be later additions to the Pali.
Moreover, the passage on “realising any state that may be realised” elsewhere in the Pali Canon always follows the jhanas, never mindfulness (C.f. AN3.101, AN3.102, AN5.23, AN5.28, AN9.35). So the whole passage is out of place in MN119.
It seems clear to me these three similes don’t belong in MN119. They seem to come from AN5.28, which makes it likely the jhana similes come from there too.
As to the six identical benefits found in both AN5.28 and MN119, these are also found in the Chinese parallel. Contextually they are a bit out of place there too, as these results normally also follow the jhanas, not sati. It could be intended here not as a direct benefit of sati, but as an eventual benefit, which happens only after the jhanas, which are also mentioned as a benefit of sati. Perhaps these six benefits are what MN119 and AN5.28 originally shared. They may be what made the reciter include the rest of AN5.28, along with the similarity of the word “kaya”. Or perhaps these six are later additions to a root text, that found their way into both MN119 and MA81.