One of my favorite authors and thinkers, C. S. Lewis beautifully illustrates how God uses the diversity of His followers to reflect His image:
To become new men means losing what we now call ‘ourselves’. Out of our selves, into Christ, we must go. His will is to become ours and we are to think His thoughts, to ‘have the mind of Christ’ as the Bible says. And if Christ is one, and if He is thus to be ‘in’ us all, shall we not be exactly the same? It certainly sounds like it; but in fact it is not so.
It is difficult here to get a good illustration; because, of course, no other two things are related to each other just as the Creator is related to one of His creatures. But I will try two very imperfect illustrations which may give a hint of the truth. Imagine a lot of people who have always lived in the dark. You come and try to describe to them what light is like. You might tell them that if they come into the light that same light would fall on them all and they would all reflect it and thus become what we call visible. Is it not quite possible that they would imagine that, since they were all receiving the same light, and all reacting to it in the same way (i.e. all reflecting it), they would all look alike? Whereas you and I know that the light will in fact bring out, or show up, how different they are. Or again, suppose a person who knew nothing about salt. You give him a pinch to taste and he experiences a particular strong, sharp taste. You then tell him that in your country people use salt in all their cookery. Might he not reply ‘In that case I suppose all your dishes taste exactly the same: because the taste of that stuff you have just given me is so strong that it will kill the taste of everything else.’ But you and I know that the real effect of salt is exactly the opposite. So far from killing the taste of the egg and the tripe and the cabbage, it actually brings it out. They do not show their real taste till you have added the salt.
From chapter 33, “The New Men,” in Mere Christianity.
If you’re not familiar with Lewis’ use of salt and light, he is referring to Jesus’ words from his Sermon on the Mount:
“You are like salt for the whole human race. But if salt loses its saltiness, there is no way to make it salty again. It has become worthless, so it is thrown out and people trample on it.
“You are like light for the whole world. A city built on a hill cannot be hid. No one lights a lamp and puts it under a bowl; instead it is put on the lampstand, where it gives light for everyone in the house. In the same way your light must shine before people, so that they will see the good things you do and praise your Father in heaven.” ~ Matthew 5:13-16 (GNT)