'Demon' in the Bible

The crowd answered and said, Thou hast a demon: who seeks to kill thee?

The Jews answered and said to him, Say we not well that thou art a Samaritan and hast a demon?

Jesus answered, I have not a demon; but I honour my Father, and ye dishonour me.

The Jews therefore said to him, Now we know that thou hast a demon. Abraham has died, and the prophets, and thou sayest, If any one keep my word, he shall never taste death.

but many of them said, He has a demon and raves; why do ye hear him?

Others said, These sayings are not those of one that is possessed by a demon. Can a demon open blind people's eyes?