Exodus 37:1

Then Bezalel made the ark of acacia wood; two and a half cubits was its length, a cubit and a half its width, and a cubit and a half its height.

Surrounding context

37:1 Then Bezalel made the ark of acacia wood; two and a half cubits was its length, a cubit and a half its width, and a cubit and a half its height.

37:2 He overlaid it with pure gold inside and outside, and made a molding of gold all around it.