Get post content and show it in a div

OK, I managed to make it work, here’s how i did :

Jquery part :

jQuery(".post-link").click(function(){
    var post_id = jQuery(this).data('id');

    jQuery.post(
        ajaxurl,
        {
            'action': 'load_post_content',
            'the_ID': post_id
        },
        function(response){
            jQuery('#the-post-content').html(response);
        }
    );

    return false;
});

And the function.php part :

add_action( 'wp_ajax_load_post_content', 'load_post_content' );
add_action( 'wp_ajax_nopriv_load_post_content', 'load_post_content' );

function load_post_content() {

    $the_post_id = $_POST['the_ID'];
    $args = array(
        'post_type' => 'post',
        'p' => $the_post_id
    );

    $ajax_query = new WP_Query($args);

    $the_content;

    if ( $ajax_query->have_posts() ) : while ( $ajax_query->have_posts() ) : $ajax_query->the_post();
        $the_content = the_content();
    endwhile;
    endif; 

    echo $the_content;

    wp_reset_postdata();

    die();
}

Hope it can help !