BibTeX:
@incollection{Various,
  author = {Various},
  title = {The Báb answered and said: ''What you have witnessed is true and undeniable},
  booktitle = {bahaistories.com archive},
  url = {https://bahaistories.com/subject/atonement},
}

APA:
Various. The Báb answered and said: ''What you have witnessed is true and undeniable. In *bahaistories.com archive*.

MLA:
Various. "The Báb answered and said: ''What you have witnessed is true and undeniable." *bahaistories.com archive*, n.d..

Chicago:
Various. "The Báb answered and said: ''What you have witnessed is true and undeniable." In *bahaistories.com archive*, n.d..