documentclass{article}
usepackage{tocbibind}
usepackage{etoc}
begin{document}
etocsetnexttocdepth{section}
tableofcontents
section{A section}
subsection{A subsection of a section}
subsection{Another subsection of a section}
section{Another section}
subsection{A subsection of another section}
subsection{Another subsection of another section}
end{document}

documentclass{article}
usepackage{etoc}
usepackage{tocbibind}
begin{document}
etocsetnexttocdepth{section}
tableofcontents
section{A section}
subsection{A subsection of a section}
subsection{Another subsection of a section}
section{Another section}
subsection{A subsection of another section}
subsection{Another subsection of another section}
end{document}