The best "sign" a true Christian can show to others of their faith is a life of loving, humble and faithful actions towards those around them.
Without those things, all the other "signs" are just trappings, trinkets and junk.
"If I speak in the tongues of men and of angels, but have not love, I am a noisy gong or a clanging cymbal. And if I have prophetic powers, and understand all mysteries and all knowledge, and if I have all faith, so as to remove mountains, but have not love, I am nothing. If I give away all I have, and if I deliver up my body to be burned, but have not love, I gain nothing."
- Paul
(That passage always blows me away!)
The best "sign" a true Christian can show to others of their faith is a life of loving, humble and faithful actions towards those around them.
I read a passage in Cor. II a few nights past, and it spoke of the flock keeping its shepherds, and reciprocity and all that. I love St. Paul.
I think Christian Love is held in such high regard by St. Paul because it is the hardest to master. Complete humility is required, and that's probably why it's so pleasing to The Lord.