Once, when the Chida was on one of his travels in the lands of Ashkenaz, one of the Admorim asked him to relate a story that described his Rebbe’s holy avoda in nigla and in nistar, and here is one of the tales he told:
The Ohr HaChaim had a special minhag to prepare himself to make Kiddush on Shabbos. Every Erev Shabbos he would sit and study and review with his talmidim the laws of testimony and witnesses – Hilchos Eidus in the Rambam. They would especially review the laws dealing with what things disqualified a witness and rendered him posul – unfit to give testimony. They studied this in order to do full teshuva [over any of these disqualifications.] Not only did the Ohr HaChaim do this as a preparation before making Kiddush, but when he picked up the Kiddush cup to recite the berocha over it, he would be aflame with such excitement and thoughts of teshuva and kedusha that all those present were also seized with pangs of regret and remorse so great that they would beg and plead that they too should merit to be eidim kesherim (proper witnesses) to testify to the Creation of the world in six days! (By Rav Yitzchok Alfaya in Kuntres HaYachieli Section Bais Hashem Chapter Middos Tovos #18)
