BibTeX:
@incollection{Various,
  author = {Various},
  title = {Arthur Parsons once commented to ‘Abdu’l-Bahá that he wished all the blacks…},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/race-unity},
}

APA:
Various. Arthur Parsons once commented to ‘Abdu’l-Bahá that he wished all the blacks…. In *bahaistories.com archive*.

MLA:
Various. "Arthur Parsons once commented to ‘Abdu’l-Bahá that he wished all the blacks…." *bahaistories.com archive*, n.d..

Chicago:
Various. "Arthur Parsons once commented to ‘Abdu’l-Bahá that he wished all the blacks…." In *bahaistories.com archive*, n.d..