BibTeX:
@incollection{Bahullh,
  author = {Bahá'u'lláh},
  title = {The Ambassador's Commendation},
  booktitle = {Epistle to the Son of the Wolf},
}

APA:
Bahá'u'lláh. The Ambassador's Commendation. In *Epistle to the Son of the Wolf*.

MLA:
Bahá'u'lláh. "The Ambassador's Commendation." *Epistle to the Son of the Wolf*, n.d..

Chicago:
Bahá'u'lláh. "The Ambassador's Commendation." In *Epistle to the Son of the Wolf*, n.d..