BibTeX:
@incollection{AbdulBah1943,
  author = {'Abdu'l-Bahá},
  title = {The Part Is Expressive of the Whole},
  booktitle = {Bahá'í World Faith},
  year = {1943},
  publisher = {Bahá'í Publishing Trust},
  url = {https://www.gutenberg.org/ebooks/19239},
}

APA:
'Abdu'l-Bahá. (1943). The Part Is Expressive of the Whole. In *Bahá'í World Faith*. Bahá'í Publishing Trust.

MLA:
'Abdu'l-Bahá. "The Part Is Expressive of the Whole." *Bahá'í World Faith*, Bahá'í Publishing Trust, 1943.

Chicago:
'Abdu'l-Bahá. "The Part Is Expressive of the Whole." In *Bahá'í World Faith*, Bahá'í Publishing Trust, 1943.