Try this

     <?php global $post; ?>
        <article id="post-<?php the_ID(); ?>" <?php post_class( \'entry\' ); ?><?php echo et_fable_get_background(); ?>>
            <div class="container clearfix">
                <header class="entry-title">
                <?php if ( is_single() ) : ?>
                    <h1><?php the_title(); ?></h1>
                <?php else : ?>
                    <h2>
                        <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
                    </h2>
                <?php endif; ?>

                    <?php //et_fable_post_meta(); ?>
                </header>

            <?php if ( ! is_single() ) : ?>
                <div class="entry-content clearfix">
                    <p><?php truncate_post( 900 ); ?></p>
                </div> <!-- .entry-content -->
                <?php //This is page id or post id
        $content_post = get_post($post->ID);
        echo $content = $content_post->post_content;

         ?>
                <footer class="entry-footer">
                    <a href="<?php the_permalink(); ?>" class="read-more"><span><?php esc_html_e( \'Read More\', \'Fable\' ); ?></span></a>
                </footer>

            <?php endif; ?>

            </div> <!-- .container -->

            <?php if ( is_single() ) : ?>
                <?php get_template_part( \'includes/share\', get_post_format() ); ?>
            <?php endif; ?>

<?php echo apply_filters(\'the_content\', $post->post_content); ?>



        </article> <!-- .entry-->