the Sacred Vail: The High Priest: Alone Allowed to Enter Within
Source: TTT
Hebrews 9:6, 7
When everything had been prepared in this way, the priests entered regularly into the first room to perform their sacred duties. / But only the high priest entered the second room, and then only once a year, and never without blood, which he offered for himself and for the sins the people had committed in ignorance.