Label block quote like displayed equation

Question

I would like to be able to add a tag to a block quote in a more or less identical manner as one would with a displayed question. Ideally, I would also be able to use \label and \eqref (or \ref) as if they quote were actually an equation.

You might say that I would like to combine the functionality of the below two examples. Is there a simple way to do this?

\documentclass{article}

\usepackage{csquotes}
\usepackage{lipsum}


\begin{document}

This is a displayed quote.
\begin{displayquote}
\lipsum[1]
\end{displayquote}
That was a displayed quote.

\end{document}

and

\documentclass{article}

\usepackage{amsmath}

\begin{document}

This is how I would like to label my block quote.
\begin{equation}
\tag{A}3x^2+1=5.
\end{equation}

\end{document}

Answer 1

You can set anything inside an equation, including a \parbox (or other textual components like a minipage or tabular). Here's an example:

\documentclass{article}
\usepackage{lipsum,amsmath}
\begin{document}
This is a displayed quote.
\begin{equation}
  \tag{A}\label{eq:A}
  \parbox{\dimexpr\linewidth-4em}{%
    \strut
    \lipsum*[1]%
    \strut
  }
\end{equation}
That was a displayed quote~\eqref{eq:A}.
This is how I would like to label my block quote~\eqref{eq:B}:
\begin{equation}
  3x^2 + 1 = 5.\label{eq:B}
\end{equation}
\end{document}

Depending on the textual content inside the equation, you may want to add \struts to achieve an appropriate baseline skip.

Note that this "quote" will not break across the page boundary, similar to an equation.