“You shall not bear false witness against your neighbor” (Ex. 20:16; Deut. 5:20).
I once read an otherwise intelligent unbeliever state that the reason he didn’t believe in the God of the Bible is because, according to the 9th Commandment, God only condemned misrepresenting the truth when one is under oath as a “witness” in a court case. So, the God of the Bible, he oddly concluded, is OK when people lie outside of court, and that was a standard that was inferior to his own!