Rashi on Deuteronomy
ועמדו שני האנשים THEN BOTH THE MEN ... SHALL STAND [BEFORE THE LORD] — Scripture here is referring to the witnesses, and teaches firstly that no evidence is valid when given by women, and teaches secondly that they (the witnesses) must submit their testimony while standing (Shevuot 30a; cf. Sifrei Devarim 190:1-3).
Rabbeinu Bahya
ועמדו שני האנשים, “then the two men shall stand, etc.” the “men” are the witnesses. The verse teaches that testimony has to be given while standing. Also, the word האנשים means that women do not qualify as witnesses.
Siftei Chakhamim
Our passage refers to the witnesses, etc. Rashi is answering the question: Do two people become involved in a court dispute but three people not become involved in a court dispute? Furthermore, the verse should have said, “And those who are involved in the dispute shall stand,” because women too can be litigants! Therefore the verse must be talking about witnesses.