The Mercy Seat was not really a seat.

There were no seats in the tabernacle, as the work of the priest was not
 finished until Christ came. Only when his work was completed, did he sit down.

"Christ, however, offered one sacrifice for sins, an offering that is effective forever,
and then he sat down at the right side of God. There he now waits until God puts his
enemies as a footstool under his feet." (Heb 10:12-13)

Christ is the Alpha (the brazen altar) and the Omega (the mercy seat) of our faith.

"I am Alpha and Omega, the beginning and the end, the first and the last." (Rev 22:13 KJV)

The mercy seat of the tabernacle was made of pure gold and had no wood in it. 

"Make a lid of pure gold." (Exo 25:17)

The gold makes the mercy seat of the tabernacle very precious,
but not as valuable as the blood sprinkled on it.

"He shall take some of the bull's blood and with his finger sprinkle it on the front of the lid and then sprinkle some of it seven times in front of the Covenant Box. After that, he shall kill the goat for the sin offering for the people, bring its blood into the Most Holy Place, and sprinkle it on the lid and then in front of the Covenant Box, as he did with the bull's blood. In this way he will perform the ritual to purify the Most Holy Place from the uncleanness of the people of Israel and from all their sins."
(Lev 16:14-16)

The gold of the mercy seat of the tabernacle spoke of the propitiation from sin. Gold refers to the divine and wood to the earthly, clearly demonstrating that propitiation (the clearing of sin) belongs solely to God.

"Herein is love, not that we loved God, but that he loved us,
and sent his Son to be the propitiation for our sins." (1Jo 4:10)

"Being justified freely by His grace through the redemption that is in Christ Jesus;
whom God has set forth to be a propitiation through faith in His blood." (Rom 3:24-25)

The lid of the covenant box inside the tabernacle was called the mercy
seat because it mercifully covered the law that was inside the Box.

"Put the two stone tablets inside the Box and put the lid on top of it." (Exo 25:21)

Two cherubim formed part of the mercy seat inside the Most Holy place
 of the tabernacle. Symbolically, they refer to Christ as the Word of God.

Cherubim is the plural of cherub. A cherub is a type of angel, having
four faces and four wings. Cherubs are the protectors of God's glory.

The cherubim were facing each other, signifying agreement between the Written
Word and the Living Word, Christ, who came to fulfill the law, not to abolish it.

"Do not think that I have come to do away with the Law of Moses and the teachings of the prophets. I have not come to do away with them, but to make their teachings come true." (Mat 5:17)

The cherubim were also looking at the blood sprinkled on the lid of the mercy seat
of the tabernacle and keeping their wings over it for protection. The Old Testament looked forward towards Calvary and the New Testament looks back at Calvary.

"Make two winged creatures (cherubim) of hammered gold, one for each end of the lid. Make them so that they form one piece with the lid. The winged creatures (cherubim) are to face each other across the lid, and their outspread wings are to cover it." (Exo 25:18-20)

'Shekinah' glory.

The Hebrew word 'shekinah' refers to the glory that is manifested through God's presence. This word, even though not found in the Bible, describes the glory found
between the wings of the cherubim on the mercy seat of the tabernacle.

"I will meet you there, and from above the lid between the two winged creatures (cherubim)
I will give you all my laws for the people of Israel." (Exo 25:22)

"When Moses went into the Tent to talk with the LORD, he heard the LORD speaking to him from above the lid on the Covenant Box, between the two winged creatures (cherubim)." (Num 7:89)

This is still the place where God meets with man, somewhere between
 the pages of His written word and the blood that was shed on Calvary.

"Let us have confidence, then, and approach God's throne (the mercy seat), where there is grace.
There we will receive mercy and find grace to help us just when we need it." (Heb 4:16)

Would you not also like to meet up with God between the wings of
the cherubim upon the lid of the mercy seat inside the tabernacle?