Aryadeva in his 400 stanzas, stress out the importance of realizing emptiness of phenomena.
You can buy his work here (kindle version):http://www.amazon.com/Aryadevas-Hundred ... 601&sr=1-1
To liberate from samsara: We just need to realize emptiness of self.
There is always a question like this: Why arhat doesn't want to come back (such as reborn or rebirth) to samsara to liberate others? Will they go to the hell to liberate all beings in the hell?
They will not. Because arhat see samsara as suffering. They see hell as something difference - full of suffering.
This is a sign they haven't realized emptiness of phenomena.
There is actually no different between nirvana and samsara. Exactly same, empty of essence.
When that person realize the emptiness of phenomena, there is no such thing called suffering. Samsara is not suffering. Samsara is also not happiness. Samsara is free from both suffering and happiness. There is no identity in this samsara. Morever, this samsara and nirvana itself are just a division created by the story of mind.
The person who realize emptiness of phenomena, cannot differentiate between hell and Amitabha pure land or other pure lands. Both just have 1 taste - empty of inherent existence.
(174) Whoever sees phenomena as like
A collection of mechanical devices
And like ILLUSORY BEINGS,
Most clearly reaches the excellent state.
(175) For those wo DO NOT ENJOY
any objects in cyclic existence
It is altogether impossible
To take pleasure in this [world].
Which arhat want to stay in this samsara? Have you heard that? This is because they don't realize emptiness of phenomena. Samsara is suffering. Who can enjoy samsara?
But if you realize emptiness of phenomena, Where is samsara? Where is nirvana?