I tried to search the internet to find the Buddha's discourse which Bikkhu Bodhi refers to in the following paragaph:
--"The Buddha also refers to Nibbana as a 'dhatu,' an element, the 'deathless element' (amata-dhatu). He compares the element of Nibbana to an ocean. He says that just as the great ocean remains at the same level no matter how much water pours into it from the rivers [the unconditioned, the pure "mind" of arahants], without increase or decrease, so the Nibbana element remains the same, no matter whether many or few people attain Nibbana."http://hkims.org/documents/Nibbana%20by
I just listened to Bikkhu Bodhi's talk "In the Buddha's words" (7d), in which he mentioned that the Buddha refers Dhamma as Brahma caria [?], the spiritual laws/principles, which is perfectly complete and purified. If some friend knows these suttas, I'd greatly appreciate to have the opportunity to read them.
Now come back to my internet search. After searching several internet engines, I only found the following relevant information to share with the friends:
―Just as the river Ganges inclines toward the sea, flows towards the sea, and merges with the
sea, so too Master Gotama‘s assembly with its homeless ones and its householders inclines
toward Nibbana, and merges with Nibbana.‖
Majjhima Nikaya 73.14
―Bhikkhus, just as the river Ganges slants, slopes, and inclines toward the ocean, so too a
bhikkhu who develops and cultivates the Noble Eightfold Path slants, slopes, and inclines toward
Nibbana.‖ Samyutta Nikaya 45.97-102
"Nibbana is sometimes referred to as the great Divine ocean and each mind of ours is like a drop entering this ocean in the experience of nibbana. This, should not be taken literally however, since our language limits us and nibbana is not limited and can not be explained by language. Nibbana is the unlimited, the unconditioned, the perfect state.
Nibbana - (Pali) Beyond all concepts of duality, the perfect, unconditioned state. It can not be described in words, but must be experienced. It is one with enlightenment. It represents the extinction of re-birth and suffering, but it is not nihilistic. The pantheistic concept of a mind being like a drop of water entering a Divine ocean with the Divine ocean being nibbana is the nearest definition, but still not adequate or entirely appropriate. It is neither existence nor is it non-existence, nor is it both; it simply must be experienced."
[Right Understanding; http://www.thedhamma.com/buddhaslists.pdf
After these efforts, I'd like to end my participation in the discussion about nibbana in this thread [but the info about the above-mentioned suttas are still most welcome]. As I mentioned in my previous post:
"it might not be really necessary to pin down the exact meaning of nibbana for liberation from greed/aversion/delusion [of the five aggregates as "self"] and from samsara, since the 1st five disciples became arahants after just detaching from the five aggregates and removing the defilements. As to what's left there which remains deathless, after removing the incoming defilements and the conditioned phenomena (five aggregates), we don't have to ponder [about it but better try to experience it].
Metta to all!