//It denotes that one who wear the sacred thread should be pure in his thought, word and deed.//
A person I know replied for this saying, absolutely not necessary; and removed his thread. The explanation he gave for this was, "A person who wears it is not all that great. Why should a thread differentiate me from others? Let the world consider me equally from now on..."
Three cheers for him (for thinking uniquely and rightly) on behalf of me and my blog!!!