Mark chapter 05

 9 Then Jesus asked him, What is your name? My name is Legion, he replied, for we are many. 

10 And he begged Jesus again and again not to send them out of the area. 

Here comes me two thoughts. First, the demons should also be able to unite as one. I remember someone among us has shared something alike, kind of that demon can do some good things as we do or something. Anyway, it reminds me to keep watching, for fear of gathering each other on the basis of physical or mental solidarity, but not of spiritual union.

Second, the man who was invaded by thoudsands of demons is indeed a warning to us, because this man must has given demons a big and comfortable house to live. Let's imagine it. Is thoudsands of demon attacked him at one time?  I think it must be one by one, or one with seven and so on(Mt 12.43-45). So, unwares, so many demons accumulated in this man's mind and he couldn't escape from their control any more. So I think of this verse (Jas 1.14-15):

14 but each one is tempted when, by his own evil desire, he is dragged away and enticed. 

15 Then, after desire has conceived, it gives birth to sin; and sin, when it is full-grown, gives birth to death. 

The sin comes from a process of pregnancy and birth, so it doesn't appear suddenly, but develope gradually nourished by our desires, bad thoughts or weakness. So, let us be good watchmen, of ourselves and also of each other!