'The Twelve' in the Bible

Then Jesus said to the Twelve, Do you also wish to go away?

Jesus answered them, Have I not chosen you, the Twelve? And one of you is a devil?

But he spoke of Judas Iscariot, the son of Simon; for it was he who was about to betray Him, being one of the Twelve.

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