I highly recommend the sutta reference provided by Christian. There is much to learn from that sutta, and it is a good translation.
Regarding what upekkha said: “Lal had said there are two types of asuras”: There are two types of asuras:
– one is called vinipatha Asuras. They belong to the apayas or the four lowest realms.
– The other is Asura Devas. They are in a Deva realm.
Those normally cannot affect humans, but more powerful devas, such as the Mara Devaputta, can affect humans.
None of them can really affect those who have strong faith in the Buddha, Dhamma, and Sangha.