You must maintain accurate and honest weights and measures, so that you may live long in the land that the LORD your God is giving you.
KJV
[But] thou shalt have a perfect and just weight, a perfect and just measure shalt thou have: that thy days may be lengthened in the land which the LORD thy God giveth thee.
ASV
A perfect and just weight shalt thou have; a perfect and just measure shalt thou have: that thy days may be long in the land which Jehovah thy God giveth thee.