God is unjust again

Deuteronomy 19:16 says," If a false witness rise up against any man to testify against him that which is wrong;" didn't the bible just say one man can not rise up against another? Why does god contradict himself like this? And if you are thinking that this i am wrong about this referring to just one man "19:17 Then both the men, between whom the controversy is, shall stand before the LORD, before the priests and the judges, which shall be in those days;" it goes on and on referring to just two men.