While Scripture does not reveal how many are guarding it, we do know that Cherubims prevent us from accessing it. The garden must be very large, because a small garden would only require one Cherubim, as they are very huge, according to the descriptions given throughout Scripture.
Exodus 37:6-9 describes the making of the Mercy Seat with the two Cherubims over it. And while I have found a variety of images that could give us a visual description of it, this is the best I could find:
One cubit equals 18-inches. The Mercy Seat in the tabernacle was 45 inches long and 27-inches wide. The cherubims were made out of one piece of pure gold, including their wings, which covered the Mercy Seat they faced.
The description given in 1 Kings 6:23-30 is of the cherubims filling the oracle within the house of The LORD that King Solomon built for God. The cherubims carved of olive tree wood were ten cubits high. Verse 24 says their wings were 5 cubits each from tip to tip. Fifteen feet high and, wing-wise, seven and one-half feet wide; HUGE. Verse 27 "And he (King Solomon) set the cherubims within the inner house: and they stretched forth the wings of the cherubims, so that the wing of the one touched the one wall, and the wing of the other cherub touched the other wall; and their wings touched one another in the midst of the house(of God).
The Book of Ezekiel has various descriptions of the actual cherubim who are always with God. Ezekiel 1:5-25; Ezekiel 41:18-19. Other references are made to cherubs in his visions, but these two sections are descriptive. Each cherub has two faces, one a man and one a lion; one face faces one direction, the other face faces the opposite direction.
But how big do you suppose the Cherubims actually are? Let's search the Scriptures and see what they do;
Isaiah 37:16---wherein God dwells
Psalm 99:1---The LORD sits between them
2 Kings 19:15; Psalms 80:1---where God dwells
Psalm 18:10--The LORD rides upon a cherub
They are The LORD's throne and chariot. They are many and do many things, as we see here. Throne; chariot; guard. I like that description in Ezekiel 1 of their movement. (I could actually visualize it this time.) These are they who stand guard over the garden of Eden.
