Siebe said: “..do you believe it is possible that one can deliberately come back to ‘this world, the 31 realms of samsara, while one is totally freed from samsara, to help other beings?”
This is a totally absurd idea in Mahāyāna Buddhism: That past Buddhas can come back to this world.
Once liberated from this world of 31 realms there is no coming back. At Parinibbana, nama and rupa are totally separated (nama rupa paricceda), and that is not a reversible process.
From the discussion that we have had on this topic, it is very clear that it is the defiled vinnana that is responsible for keeping one in this world. A Buddha (or an Arahant) will NEVER re-generate a defiled vinnana in order to REMAIN in this world.
It is only because we have a defiled vinnana that we are so reluctant (and even afraid) to be liberated from this suffering-filled world. This is especially because we are not aware of the unimaginable suffering that awaits in the apayas. Even in this world, how many people commit suicide because they just cannot bear the suffering (mental or physical), including some famous people with all the money in the world?
One can get a vague idea of the suffering in the lower realms in the apayas, by looking at the animal suffering. How many fish die of unimaginable suffering once hauled in to boats when caught in nets. They could be there for hours, writhing in pain, before dying. When a wolf pack attacks a deer, for example, they don’t kill and eat; they eat the flesh while the animal is still alive. Poeple tend to enjoy National Geographic videos where a tiger chases a deer and eats it alive. Most people are not aware that they themselves could be subjected to similar situations in future births.