Preparing for Kiddush
The Chida was once in the lands of Ashkenaz when one of the Admorim there asked for an account of his Rebbe's holy avodah, both in nigleh and in nistar. Among the things the Chida told him was a custom the Ohr HaChaim kept to ready himself for Kiddush on Shabbos.
It is told that each Erev Shabbos the Ohr HaChaim sat with his talmidim and went over the Rambam's Hilchos Eidus, with special attention to what makes a witness unfit to testify. Their aim was to do complete teshuvah for any such flaw in themselves.
Then, at the Kiddush itself, the Rebbe would take the cup and begin the berachah aflame with longing for teshuvah and kedushah. The feeling spread through the room, and everyone there was filled with remorse. Each of them pleaded to be worthy of standing as a kosher witness to Hashem's creation of the world in six days.