@Christ4Me Oh I agree.I am sure it can serve as a witness but I have seen many people wearing crosses on their necklace but their actions were void of His love.
And I indeed agree with what you say about provoking one another to brotherly love.
It's not that the symbol has some kind of magic effect; far, far from it. Instead, the truth that lies behind a witness tattoo can become a challenge to others in some circumstances. Sometimes a Christian fish symbol <>< is used instead of a cross. If someone asks, What's that? then obviously it opens up a whole possibility of testimony.