Exodus 25:17 KJV
And thou shalt make a mercy seat of pure gold: two cubits and a half shall be the length thereof, and a cubit and a half the breadth thereof.
Exodus 25:17, King James Version
In context
16 And thou shalt put into the ark the testimony which I shall give thee.
17 And thou shalt make a mercy seat of pure gold: two cubits and a half shall be the length thereof, and a cubit and a half the breadth thereof.
18 And thou shalt make two cherubims of gold, of beaten work shalt thou make them, in the two ends of the mercy seat.