BibTeX:
@incollection{Various,
  author = {Various},
  title = {Bahá'u'lláh Receives His Mission from God},
  booktitle = {Baha'i Stories for Children},
  url = {https://bahaistoriesforchildren.blogspot.com/2014/11/bahaullah-receives-his-mission-from-god.html},
}

APA:
Various. Bahá'u'lláh Receives His Mission from God. In *Baha'i Stories for Children*.

MLA:
Various. "Bahá'u'lláh Receives His Mission from God." *Baha'i Stories for Children*, n.d..

Chicago:
Various. "Bahá'u'lláh Receives His Mission from God." In *Baha'i Stories for Children*, n.d..