How to use WP_Query to display many posts?

Question

This is my WP_Query instruction but this not work. This display just first post. Help me please?

    // WP_Query arguments
    $args = array (
        'post_type' => 'teachers',
        'p' => '100, 102, 105'          <----------
    );

    // The Query
    $filter = new WP_Query( $args );

    // The Loop
    if ( $filter->have_posts() ) { ...

Answer 1

The p (post) paremeter for WP_Query accetps a single value only:

$args = array(
    'p' => 100
);

For multiple posts use post__in and pass an array of post ids:

$args = array(
    'post__in' => array(100, 102, 105)
);

See Post & Page Paremters for further clarification.