BibTeX:
@incollection{Various,
  author = {Various},
  title = {Baha’u’llah’s servant: Isfandiyar - "the essence of love, radiant with sanctity and perfection, luminous with light"},
  booktitle = {Baha'i Stories Blog},
  url = {https://bahaistories.blogspot.com/2017/08/bahaullahs-servant-isfandiyar-essence.html},
}

APA:
Various. Baha’u’llah’s servant: Isfandiyar - "the essence of love, radiant with sanctity and perfection, luminous with light". In *Baha'i Stories Blog*.

MLA:
Various. "Baha’u’llah’s servant: Isfandiyar - "the essence of love, radiant with sanctity and perfection, luminous with light"." *Baha'i Stories Blog*, n.d..

Chicago:
Various. "Baha’u’llah’s servant: Isfandiyar - "the essence of love, radiant with sanctity and perfection, luminous with light"." In *Baha'i Stories Blog*, n.d..