% In the name of Allah
\documentclass[10pt,a4paper]{paper}
\usepackage{amsmath}
\usepackage{makecell}
%\usepackage{arydshln}
\begin{document}
\begin{table}
    \setcellgapes{1em} % adjustment of row padding (makecell package)
    \makegapedcells % turn on row padding
    \centering
    \begin{tabular}{ccc}
        \hline
        header 1 & header 2 & header 3 \\
        \hline
        1 & 2 & 3 \\
        4 & 5 & 6 \\
        7 & 8 & 9 \\
        \hline
    \end{tabular}
\end{table}
\end{document}