From the beginning of creation, God sought a way to commune with man, but sin was always in the way.  In Exodus 24 and 25, God formed a plan and created a place for this communion to take place, and He told Moses, you build it this way, and I'll meet you there!  

But first, the sin issue had to be dealt with by the sprinkling of the blood of the animal sacrifices upon the elements of the tabernacle, the altar and finally, the people, themselves.  Only then could they approach the Holy God. 

God told Moses to create a place to house the tablets of stone and the testimony, which would be covered by the mercy seat—and He would commune with them there.

Thank God for the pure blood of Jesus Christ that covers our sin so that we can commune with God, having been cleansed by his blood.