Once upon a time, a group of wise Jews called the Chachamim noticed that people were following all of shabbats rules but they weren't always focused on the holiness of shabbat and thus many people were missing out on this mitzvah. In order to help connect with shabbat more they created this ritual of starting shabbat with Kiddush, a toast, that would remind everyone of the holiness of shabbat. Ultimately, this ritual is now known to be a part of kiddush all around the world and helps Jews every week complete the mitzvah of recognizing the holiness of shabbat every week!