Who could go behind the temple veil and how often?
Only the high priest, Aaron, could enter behind the veil into the Holy of Holies, and he did so just once a year on the Day of Atonement. That veil separated the sanctuary from the Holy of Holies where the Ark of the Covenant and God's presence were.
Les explains that the veil was the part in the tabernacle and later in the temple that separated the sanctuary, where priests ministered daily, from the Holy of Holies, where the Ark of the Covenant, the presence of God, and the Shekinah Glory were. Only Aaron the High Priest would go behind the veil once a year on the Day of Atonement. After Solomon's temple was built, the veil was so thick and heavy that Josephus indicates a team of oxen could not have ripped it apart. Yet it was ripped in two from top to bottom, proving men had nothing to do with it; this was a miracle working God. The veil being rent from top to bottom indicated that the way into the presence of God had been made possible by His death, because the veil in symbolism spoke of His body of flesh.