'Fast' in the Bible

And Elisha is sitting in his house, and the elders are sitting with him, and the king sendeth a man from before him; before the messenger doth come unto him, even he himself said unto the elders, 'Have ye seen that this son of the murderer hath sent to turn aside my head? see, at the coming in of the messenger, shut the door, and ye have held him fast at the door, is not the sound of the feet of his lord behind him?'