When you wear a Christian t-shirt, in a way, you could compare yourself to a Muslim woman wearing a hijab. You are basically telling everyone around you, "I am a follower of Jesus Christ." From the moment you step outside while wearing a Christian t-shirt, everyone who sees you will know Who you follow. And every move you make from that point forward will cause an impression to be made -of you, yes- but also of Jesus.
Scary, isn't it?
People make judgments based on appearance. If you wear a Christian t-shirt in public and act like a jerk, then people will inevitably look at you and think, "That's a Christian? Man, I can't stand those people." And in the back of their minds, a little voice will say, "If that's how the followers of God act... then that's how God must be too."
When you're wearing a shirt that displays your faith for all to see, everything you do and say is a witness to the people around you. People are constantly judging Christ through you.
That's easy, you might be thinking. I hardly ever cuss or steal or lie. I don't get drunk in seedy bars and beat up the people around me. I don't sell drugs. I'm a pretty good person. No big deal. But the "big stuff" isn't all you should be worried about.
Small things -like smiling- are vitally important. If you brush past a stranger and he's left thinking, "Christians are snobs," then that's a problem. Smile. Act friendly to those around you, even if you're having a bad day. If you're seen openly complaining and making negative comments and someone thinks, "I didn't know Christians acted like this," that's a problem. Think before you speak. If you're seen griping at your parents over the phone or gossiping about a friend... that's a problem.
Everything you do will be scrutinized because people think, "I wonder what Christians are like" and then look at you. 1 Timothy 4:16 warns us to be conscientious of how we live because we are being observed. People see Christ in us, no matter if we're acting like one of His disciples or not.
1 Corinthians 10:32 says, "Do not cause anyone to stumble." How would you feel if you found out that someone turned away from God because they saw your actions and thought, "I was interested in God... but I sure don't want to be like that." I've made the mistake of being a poor example for Christ. Many times. It's difficult to be a shining light all the time, but that is what we should strive to be. Matthew 5:14 calls us to be cities on a hill. People look to you when they want to see Christ.
Do I still think wearing Christian t-shirts is a good thing? Absolutely. Will I continue to wear them all the time? You bet I will. From this point forward, will I stop and think before I say or do something that might cause others to stumble? Yes.
I know I've been called to be a city on a hill. I know people judge my Savior based on my actions and words. And from now on, I will strive to be a positive example for Him wherever I go.