https://youtu.be/06JP_GFmB2k?t=17m27s
1,
'include' => $prevPost->ID
);
$prevPost = get_posts($args);
foreach ($prevPost as $post) {
setup_postdata($post);
?>
1,
'include' => $nextPost->ID
);
$nextPost = get_posts($args);
foreach ($nextPost as $post) {
setup_postdata($post);
?>