A listener recently asked advice on how to reply to a work-related e-mail from a very nice client. Even though the message was related to business, it also included an invitation to receive a link for religious material. Working in a public sector job where separation exists between church and state, the recipient was unsure how to respond and felt it inappropriate to engage the request.
Although we advise against it in professional communication, people will often include "God bless" or quotes from famous thinkers in an e-mail signature. If the link you receive is embedded in the signature, there's no need to reply about it. But if the message is a specific request for you to visit the link, consider responding by saying, "I saw the link you sent and, no, I'm not interested."
Be sure to follow that up with a polite closing such as, "talk to you soon" or "have a nice weekend," to maintain the good rapport you have with your associate.
Listen to this podcast of Awesome Etiquette to hear more on the topic.