The swords suit corresponds to the element of Air, ‘movement’, back and forth, forever changing, high to low. Here there is a warning that someone might be in our “camp” and stealing our options and opportunities before a big battle ahead. There is a spy!
In the Rider-Waite tarot image, we see the man carrying away five swords, but leaving two fixed in the ground behind him, he looks back over his shoulder to check upon them.
The Swords are thoughts, arguments, reasoning, manipulation, operations, and planning.
This card is also warning that it is not a good idea to look back on our actions, what is done is done, and in the past. Now is the time to move on and out and away from past quarrels.