Or HaChaim on Exodus 22:22/אור החיים על שמות כ״ב:כ״ב

1 אם ענה תענה אותו, If you afflict them in any way, etc." Why did the Torah have to write the word אותו, "him," and did not merely write אם תענהו, using the pronoun ending? We would have known that the subject of the verse is the orphan just mentioned. Perhaps we can best explain this with the help of the Mechilta on the words לא תענון. The author writes that but for the word לא תענון in verse 21, I would have thought that this injunction applies only to widows and orphans. Whence do I know that one must not treat people generally in an exploitative manner? This is why the Torah writes לא תענון. Thus far the Mechilta. Since the words לא תענון apply to people as a whole, the word אותו in verse 22 is needed to tell us that the special penalty in store for people transgressing this commandment spelled out in verse 23 applies only if the violation was committed against either a widow or an orphan.