This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
The most physically costly belief Knocking documents belongs to Seth Thomas, a young man who needed a liver transplant and refused, on doctrinal grounds, to accept blood transfusions as part of the procedure. Jehovah's Witnesses read a handful of biblical passages, most centrally a command in Leviticus against consuming blood, as extending to receiving blood medically as well, a position the faith holds even when a transfusion could plausibly save a life. Thomas's story gives the film its sharpest illustration of what co-director Joel Engardio, himself raised in the faith, says the whole project was built to show: that a belief many outsiders find not just unfamiliar but actively alarming can still be held sincerely, without the person holding it forfeiting the ordinary protections and respect extended to anyone else's convictions.
Alongside Thomas and Lillian Gobitas's flag salute case, the film follows Joseph Kempler, a Jewish convert to the faith and a Holocaust survivor persecuted for his own wartime refusal to bear arms, using his story to carry the film's third named practice, conscientious objection to military service. Knocking premiered at the Indianapolis International Film Festival in May 2006, later reaching a national audience on PBS's Independent Lens, and won documentary jury and audience awards at several festivals along the way. Critics covering the film, including in its Newsweek and USA Today coverage, credited its sympathetic case-by-case approach while noting it gives comparatively little screen time to a more contested Witness practice, disfellowshipping, the formal shunning of members who leave or are expelled.