WordPress - make specific post always be the latest

WordPress - make specific post always be the latest.php

/* 
    Change the date of post ID 946 to the current date.

    This is so the post is shown as the latest, thereby showing as the 
    latest post on the homepage and also as the latest post on the latest-news page.
*/
function update_post_date_daily() {

    $post = get_post(946);

    $post->post_date = current_time('mysql');
    $post->post_date_gmt = current_time('mysql', 1);

    wp_update_post($post);

}
add_action('change_post_date', 'update_post_date_daily');
wp_schedule_event(time(), 'daily', 'change_post_date'); /* Runs every day */