This Pasuk is referring to Ona'as Devarim. What is the definition of Ona'as Devarim?
Rashi: It incorporates hurting verbally 1 and giving advice that is not to the advantage of the recipient.
Seforno: It incorporates Geneivas Da'as (misleading verbally) and and giving bad advice - even if one gains nothing by doing so.
Bava Metzi'a, 48b: One should not say to a Ba'al Teshuvah 'Remember when you used to sin!' or to a Ger who comes to learn Torah 'How can a mouth which ate Neveilos and T'reifos learn Torah?'.
Why does the Torah write "Al Tonu Ish es Amiso" am d not 'es Achiv'?
Bava Metzi'a, 59a: In order to Darshen "Am she'Itcha"
As if "Amischa" was spelt with an 'Alef'. See Torah Temimah, note 106.
Why does the Torah inseret "Veyareisa me'Elokecha"?
Why does the Pasuk add the phrase "Ki Ani Hashem Elokeichem"?
Seforno: 'I am the G-d of both the buyer and the seller', Hashem is saying, 'and I am particular about either of the one cheating the other'.