“Look, up in the sky, it’s a bird, it’s a plane — no, it’s Superman!”
How did the people know it was Superman? He could fly for one thing! He was faster than a speeding bullet; more powerful than a locomotive; able to leap tall buildings in a single bound! How did they know it was Superman? By what he did!
Suppose you heard this: “Look, down the street, it’s a Buddhist, it’s a Muslim — no, it’s a Christian!” On what basis could that judgment be made? You’d have to use the same criteria used on Superman: What does he do? What characterizes her life? Of course it goes without saying: What he/she believes is also critical!
This Christian person might not be leaping tall buildings in a single bound; she might be slow as molasses! But mark this well: Though at times weak and imperfect, the overall pattern of a genuine Christian’s life is one of obedience to Jesus Christ (I John 3:7-8).