Authenticity of Statement Regarding Umar RA Forbading Enslavement of Arabs

There is statement which is famous among people and in English books related to Biography of Umar رضي الله عنه. It is stated that > Umar رضي الله عنه during his caliphate forbade the enslavement of Arab (whether they are > Muslims or Non-Muslims] and even order to Free any Arab Slaves along > slaves who captured during Riddah Wars of Abu Bakr رضي الله عنه. But I haven't come across any scholars' texts mentioning this. Many point towards **"Shurut al-Umariyyah (شروط العمرية)"** but I have found only شرح of it and even those شرح doesn't mention what is being claimed. So what is authenticity of claim being made regarding Umar رضي الله عنه order on enslavement of Arabs?