"You can't judge my faith!" A person says after you have asked them to come back to worship or you approach them about the way that they are living their faith. Instantly, when we bring up concerns about their faith walk, BOOM, "You can't judge my faith!"
Can we judge faith? No. That is between God and the person. So then are our hands tied? We just stand back when they quote a passage from the Bible that says, "Don't judge." However, are we called to address our brothers sins (Matthew 18)? Yes! Yet, we should probably use a different language. Instead of using "faith" language, say something like this, "You are not living out your sanctified Christian life accordingly." Then if they say, "You can't judge my faith" You can come back with: "I'm not, I'm concerned about your Christian walk."