If the Torah commands us "You shall be holy, for I the Lord your God am holy" immediately after prohibiting actions like gossip, revenge, and holding grudges, is kedusha (holiness) primarily about what we *avoid* doing to others, rather than mystical practices or ritual perfection?

No, kedusha is not primarily about what you avoid. It's much deeper than that. When HaKadosh Baruch Hu says in Parashat Kedoshim "You shall be holy because I am holy," He's teaching us something fundamental about what it means to be a Jew. Holiness is not just about refraining from gossip, revenge, and grudges - though these are certainly part of it. Kedusha is about imitating Hashem Himself. As He is holy, you be holy. As He is compassionate, you be compassionate. As He is gracious, you be gracious. The Torah places kedusha right there with the interpersonal commandments to teach you that holiness encompasses everything - your relationship with Hashem and your relationship with people. You cannot separate them. Rashi and the Ramban both explain that kedusha primarily refers to morality and intimacy - how you conduct yourself in the most private areas of your life. It's about managing yourself even with things that are permitted to you. Just because something is allowed doesn't mean you should do it like an animal. The Ramban teaches us that kedusha means you don't become a degenerate within the parameters of what's permitted in the Torah. A person could keep kosher but eat like a pig. A person could be with his wife but act like a rooster. That's not holiness. Holiness requires you to elevate yourself beyond just technical observance. You manage your consumption, your speech, your desires - everything. So when the Torah puts these commandments together - don't gossip, don't take revenge, don't hold grudges, and be holy - it's showing you that kedusha affects every aspect of your life. It's not mystical mumbo jumbo. It's practical. It's about character development, middot. Working on your character traits is real teshuva. Anyone can stop murdering - even a monkey knows not to kill. But working on arrogance, anger, jealousy, speech - that's the real work of becoming kadosh. And let me be clear - you must understand that kedusha is the foundation of all of Judaism. Without it, nothing else works. You can pray all day, learn Torah all day, but if you're not working on your kedusha - if you're looking at things you shouldn't look at, speaking lashon hara, being immodest - you won't achieve anything. The more you understand your own flaws and work on fixing them, the more merciful you become toward others. When you're judgmental of yourself for the sake of positive growth, you become less judgmental of others. So kedusha is not primarily about avoidance - it's about transformation. It's about becoming like Hashem. That includes avoiding the negative, yes, but it's much more about actively pursuing holiness in every action, every thought, every relationship. That's what separates us from the nations of the world. That's what makes us Am Yisrael.