The Major Arcana Tarot Card allocated to the sign of Libra is the Justice card. The general meaning of this card is truth, balance, equilibrium and order. Libra is also the sign of partnerships, as it rules the 7th House.
The Minor Arcana Cards of the Two, Three and Four of Swords have less obvious connections to the sign of Libra. Each Suit corresponds to an element, and the Suit of Swords corresponds to the element of Air, the intellectual or mental plane. Since Libra is an Air sign, it corresponds to the Suit of Swords.
When a Decan Wheel is consulted (see image below), the first Decan of Libra is found to correspond to the Two of Swords. The second Decan corresponds to the Three, and the third Decan to the Four. If your Sun sign is Libra, you can determine which minor card is “your” card by seeing where your birthday falls in the chart below. It can be used as an alternate Identifier, or you may contemplate how the card is thematic in your life. Additionally, using the Decan Wheel allows for time to be introduced into readings.
What exactly is a Decan Wheel? A “Decan Wheel” divides a circle, which has 360 degrees, into 36 10-degree segments (“dec” means 10.) Each of these 36 segments correspond to one of the Minor Arcana cards in the Tarot, excluding the Aces and the Court Cards. The 36 segments are grouped into 12 groups of 3. The 12 groups are the Zodiac signs, and the 3 within those groups are the Cardinal (1st decan), Fixed (second decan) and Mutable (third decan) sub-aspects of each sign. So for example if your birthday is October 6, your birthday falls within the approximate 10- day segment of the 2nd decan of Libra. This indicates your birthday is a Fixed sub-aspect (the 2nd decan) of a Cardinal sign (Libra), and corresponds to the 3 of Swords. Reflecting on your particular set of aspect & correspondence will undoubtedly inspire insights about yourself and your life.