the Keruvim

And the Keruvim shall stretch out their wings on high... and their faces shall look one to another (25:20)

But in another verse (II Chronicles 3:13) it says, "they faced the walls of the room"? 

When the people of Israel fulfilled G-d's will, the Keruvim would face each other; and when the people of Israel did not fulfill G-d's will, the Keruvim would face the walls of the room.

(Talmud, Bava Batra 99a)