Used on single post permalink pages, this template tag displays a link to the previous post which exists in chronological order from the current post.

wp-post-next-previous-link.php

<?php
/*
previous_post_link( $format, $link, $in_same_term = false, $excluded_terms = '', $taxonomy = 'category' );
*/

previous_post_link('%link', 'Previous in category', TRUE, '12');
previous_post_link( '%link', 'Previous post in category', TRUE, ' ', 'post_format' );

// Using font-awesome icon in link custom buttom
previous_post_link( '%link', '<i class="sprite sprite-left-arrow"></i>', TRUE, ' ', 'status' );