\documentclass{article}


\usepackage{amsmath}

\begin{document}

$
\begin{CD}
A @>>> B @<<< C \\
@VVV @AAA @| \\
D @>f>l> E @= F \\
@VbVjV @AbAjA \\
G @<f<l< H
\end{CD}
$

\end{document}