Nimoy wrote for the Star Trek blog that he had grown up in Boston’s West End neighborhood, which was home to a large number of immigrants. He attended a local Orthodox Jewish synagogue with his family. They were particularly observant of the Jewish High Holidays. His father once instructed young Nimoy not to look at the priests as they prepared to say the benediction that included the gesture, as “it is believed that during this prayer, the ‘Shekhina,’ the feminine aspect of God comes into the temple to bless the congregation” and the accompanying light could be damaging. Some people traditionally close their eyes to protect them. Nimoy secretly peeked and recalled that upon seeing “the split-fingered gesture of these men … I was entranced. I learned to do it simply because it seemed so magical.” Around 25 years later he introduced a version of the hand sign as the Vulcan salute, accompanied with its own blessing: “Live long and prosper.”
Writer Lindsay Traves explored the history of the Vulcan salute for the Star Trek blog in 2019 in honor of Jewish History Month. Rabbi Howard Morrison of Toronto’s Beth Emeth Synagogue explained that the gesture, made with both hands with thumbs connected, forms the Hebrew letter Shin, which is the first letter of Shaddai, one of the names for God in the Torah. The gesture didn’t come easily to all “Star Trek” actors; per the IMDb, Celia Lovsky had to have her fingers taped together in order for T’Pau to return Spock’s greeting.