“And no man puts new wine into old wineskins, or else the new wine will burst the skins, and itself will be spilled, and the skins will perish.”
The point is emphasised again using the idea of putting new wine into old wineskins. To do so would be to cause the dried out old skins to burst. They are no loner elastic enough to cope with the fermentation of new wine. Then all would be lost, the new wine and the wineskins, for the skins would perish.
As the parallel above reveals this includes the idea that in order for the new to prosper there must be His death. Because Jesus has come to a place which is like dried out, old wineskins, His having come can only result in His death (the new wine will be lost) and the destruction of the place to which He has come (the old wineskins, Jerusalem, will perish).