Naturality Square

Given two Categories and , and two functors , and a Natural Transformation between them, and given a Morphism between Objects and a naturality square of at is:

\usepackage{tikz-cd}
\begin{document}
\begin{tikzcd}
FA \arrow[r,"Ff"] \arrow[d,"\alpha_{A}"]
 & FB \arrow[d,"\alpha_{B}"] \\
GA \arrow[r,"Gf"]
 & GB
\end{tikzcd}
\end{document}

By the definition of Natural Transformation, this is always a Commutative Diagram i.e.