'The Twelve' in the Bible

Jesus said therefore unto the twelve, Would ye also go away?

Jesus answered them, Did not I choose you the twelve, and one of you is a devil?

Now he spake of Judas the son of Simon Iscariot, for he it was that should betray him, being one of the twelve.

But Thomas, one of the twelve, called Didymus, was not with them when Jesus came.