The Four of Swords (Four of Wind in the Penguin tarot deck) is the card that represents rest in the Minor Arcana. This is the card that shows up when you need to recharge your batteries or recuperate. You need the time to relax after dealing with some hard challenges. And this is also the card that represents meditation and contemplation.
The thing is that life is full of challenges and you know this. But how can you possibly take on the next challenge if you are burning out? This is why you need to rest. You need extra sleep if necessary. You need respite. This is the only way you can recharge so you can face the world again and tackle new challenges that are coming your way. Therefore, if you have been through something that has been physically or emotionally taxing, you must break and rest so you can go out and face the issue that is taxing you again with renewed energy.
Imagine an athlete who has run several marathons. He cannot keep going if he doesn’t take a break. He needs to take some time to sit down, have a healthy drink and snack, and rest so he develops the energy to go for the next round.
When the Four of Swords shows up in reverse, it can mean you are very deep with contemplation or you have not rested enough. This is when it shows that you are burned out and exhausted. It can also represent resting too long or too much to the point of stagnation.
Astrologically, this card is linked to Jupiter in Libra.