Cant get the content to show.

single.php

<?php get_header(); ?>

<p>Single.php</p>

<div class="container">
	<div class="row">
		
		<div class="jumbotron">

        <div class="container">

            <h1 class="blog-title"><?php bloginfo( 'name' ); ?></h1>
    
            <?php $description = get_bloginfo( 'description', 'display' ); ?>
    
            <?php if($description) { ?><p class="lead blog-description"><?php echo $description ?></p><?php } ?>

        </div>

    </div>
		<div class="col-sm-8 blog-main">
		<article id="post-<?php the_ID(); ?>" <?php post_class("block"); ?> role="article">

            <div class="blog-post">
            <h2 class="blog-post-title"><a href="<?php the_permalink(); ?>" title="Read more"><?php the_title(); ?></a></h2>
            <p class="blog-post-meta"><?php the_date(); ?> by <?php the_author(); ?></p>
            <?php ( the_post_thumbnail( 'category-thumb600' )) ?>
            <?php the_content(); ?>
        </div><!-- /.blog-post -->

        </article>
		</div><!--col-sm-8 blog-main -->
	
		<?php get_sidebar("left"); ?>
		<?php get_sidebar("right"); ?>
	
	
	</div> <!--row --> 
</div> <!-- /container -->
<?php get_footer(); ?>