When someone else sees you do you wonder what they actually see or maybe you don't mind? Sometimes what we think we are showing it not what is actually seen, we just don't realise it. Theres that expression "don't judge a book by its cover" and then there is "don't go on first impressions". I was once told by one of my bosses that when I interviewed potential employees that my wearing smart clothes and a tie was too intimidating for the candidates (potential software engineers). He may well have been right, but its what I was taught earlier in my career. Funnily enough when I lived in Italy I was told to dress up, it was expected of senior people that they look the part - "la bella figura".
Perhaps more importantly we should ask of ourselves - what does my lifestyle say about me, does it talk of a person in love with an incredible saviour or of something else? It is so easy to get submerged in the culture we live in and find ourselves adapting to that rather than seasoning it, as salt should do. The clothes we wear, the things we take with us (i-pod, mp3, smart phone ...), the books we read (if we read at all) and the films we watch all say a lot about us and what we find ok and not ok.
In my elementary physics lessons, a few years back, we played with prisms (glass pyramids), experimenting with what happens when you shine light into it. The result is that the light is split up and focused through the other faces of the prism, what goes in produces what comes out and is seen. A diamond is even more dramatic, as light shines onto it, it is reflected from and refracted through the facets (sides) of the diamond which sparkles. But, and here is the key, no light on the diamond means that it cant reflect, refract or sparkle.
The same is true for us as Christians, we can culturally engage, do the latest things, have clever, witty answers to the popular questions. But in the end those looking at us will be asking what does their lifestyle say about what they believe, can we see the truth of their words in their lives? Our walk is a daily walk with Christ, through prayer, through hearing or reading God's word in scripture, through meeting together, through sacrifice of ourself and listening to God as he directs our paths to do what he has planned for us to do.
Think of the impact of a diamond, its hard to ignore, if we let the light of Christ illuminate our lives daily, it will transform us and then like the diamond we will shine for him and the truth of what we say we believe will be borne our in our lives. The results are surprising, but then we believe in a surprising God.