לזכר נשמת ר' יצחק עמרם אליהו בן ר'אברהם אשי זצ"ל
יום השנה, יום ב' דראש השנה
The Taz (Y.D. 242 : 13) writes “ it is not necessary to stand up when the Aron Hakodesh
Is opened. People who do so, do it for the Kavod of the Sifrei Torah.
The Chasam Sofer (C.M. 73) writes , someone who is suspect to swear a false oath, in order
to scare him you may not force him to lay down in a casket and make the Shevua (oath).
One of the reasons is because you need to stand when the* the Aron Hakodesh is open.
*They used to open the Aron Hakodesh and light black candles, so to scare them not
to make a false oath.