Here in Guatemala you see many products with the Nike logo, but many of them (most of them sold on the streets) are not authentic. Why would people put the Nike logo on their products? Because the original Nike products have a reputation for good quality, and for that reason have a higher value. These people desire to give their products an image of quality to be able to sell more of them and at a higher price than the unbranded products of equal quality. There would be no reason to steal the Nike logo if the original product did not have a proven higher value.
We can apply this same principle to Christianity. Not everyone that calls themselves “Christian” is necessarily authentic. The reason that they would like to appear as such would be the proven quality and value of the real thing. Instead, they produce a cheap imitation, without the investment and sacrifice that would be part of authentic Christianity.
The reputation of the authentic Nike products is not damaged by the poor quality of the imitations. If anything, the constant illegal use of the logo strengthens their good reputation; if their products weren’t so good, they wouldn’t be worth imitating. However, when it comes to false Christians, many form their opinion of the Gospel based on the imitation, and use them as an excuse to reject God. (It would be foolish to use that excuse to denigrate Nike products!)
How can one know the difference? For either sports products or Christianity, the answer lies in the origin. Where was the t-shirt produced? What is the origin of the claim of the person who gives themselves the Christian “logo”?
“Consequently, by their fruits you shall know them.” (Matt. 7:20)
“Examine yourselves, whether you are in the faith; test yourselves. Or do you not yourselves perceive that Jesus Christ is in you, unless you are disapproved?” (2 Cor. 13:5)
“For the time has come for judgment to begin at the house of God…” (1Pet. 4:17)