We can understand the need for divine, individual and social justice, but when the Justice card shows up in a tarot reading, her meaning can seem too broad, too vague, and difficult to understand in the context of a reading that hardly involves anything to do with the Supreme Court or the Final Judgement of your soul. Divinatory meanings pare things down to manageable size somewhat. Justice can represent a legal matter in a querant's life, a divorce, any kind of legal document or contract. She bodes well for such things and assures the seeker that things will likely shake out in your favor, or at least fairly. She can tell you you're in the process of making a Big Decision in your life. As a Major Arcana, she represents matters of destiny, big choices that impact the course of your life. As advice she urges you to consider all the evidence, weigh it, and above all: Be Fair! Sometimes you may need to cut something out of your life in the process of balancing those scales or add something in order to find that equilibrium. Her sword, just like all the swords in tarot, represents wisdom and communication, but it also stands for just punishment for wrongdoers. Be careful where you point that thing.
More often than not, as a Major it represents a decision that will impact you rather than one you have to make. It can point to events occurring through which divine justice will be evidenced, karmic balance. There's no need to fear Justice's sword unless you've been racking up check marks in the naughty column. Even so, you will know that when it comes down you deserved it. Above all, she is fair and there isn't any railing against her, even though you might be kicking your own backside up the street.