For God’s will was for us to be made holy by the sacrifice of the body of Jesus Christ, once for all time. Hebrews 10:10
Recently I have been reading chapters of Exodus and Leviticus which describe how the tabernacle was set up and Aaron and his sons ordained as priests. Every item in the tabernacle was anointed with oil and sprinkled with blood to make it holy. The priests and the priestly garments were also anointed with oil and sprinkled with blood before they could minister. When everything was consecrated by the blood and the anointing oil, the regular sacrificial system was started with great solemnity. Finally all the Israelites saw the glory of the Lord fill the temple.
How elaborate the system was under the Old Covenant for the people to enter God's holy presence. Even so only the priests could enter the Holy Place - the ordinary Israelites were not allowed to enter and had to stay in the outer court.
In contrast, living under the New Covenant, our access into God's presence has been made simple. The sacrifice for our sins has been made for us by Jesus Christ; we are sprinkled with His blood to make us holy. He is our great High Priest who ministers to us and enables us to enter in, not only to the Holy Place but to the Holy of Holys'.
And what do we do? We believe.
And so, dear brothers and sisters, we can boldly enter heaven’s Most Holy Place because of the blood of Jesus. Hebrews 10:19