I can't refer it to anywhere in Bible, most probably there is no such relation. But as I understood the severity of this issue in JW context was based on the idea that partaking is lead by the understanding of partakers position given by the holy spirit. Any other person touching those emblems would be in risk of offending the holy spirit as this understanding of their anointed status was not given. The bad and dangerous thing here was actually the fact that as holy spirit is not a person, it cannot forgive you in any possible manner, thus potentially subjecting any unworthy partaker to already been irrevocably judged.
This is more or less the lesson I was given.
CP