BibTeX:
@incollection{AbdulBah1978,
  author = {'Abdu'l-Bahá},
  title = {That Which Eternally Endureth: The Master on Detachment},
  booktitle = {Selections from the Writings of 'Abdu'l-Bahá},
  year = {1978},
  publisher = {Bahá'í World Centre},
  url = {https://www.bahai.org/library/authoritative-texts/abdul-baha/selections-writings-abdul-baha/},
}

APA:
'Abdu'l-Bahá. (1978). That Which Eternally Endureth: The Master on Detachment. In *Selections from the Writings of 'Abdu'l-Bahá*. Bahá'í World Centre.

MLA:
'Abdu'l-Bahá. "That Which Eternally Endureth: The Master on Detachment." *Selections from the Writings of 'Abdu'l-Bahá*, Bahá'í World Centre, 1978.

Chicago:
'Abdu'l-Bahá. "That Which Eternally Endureth: The Master on Detachment." In *Selections from the Writings of 'Abdu'l-Bahá*, Bahá'í World Centre, 1978.