Pass Paged
into parameter array of query_posts
You should set get_query_var( 'paged' );
if you want your query to work with pagination.
$paged = (get_query_var('paged')) ? get_query_var('paged') : 1;
$args_news= array(
'cat' => 1,
'posts_per_page' => 2,
'orderby' => 'post_date',
'order' => 'DESC',
'numberposts' => -1,
'paged' => $paged,
);
query_posts( $args_news );
if ( have_posts() ) :
while ( have_posts() ) :
the_post();
the_title();
the_content();
endwhile;
endif;
for more information:https://codex.wordpress.org/Pagination