Working fine, reference to content working.

index.php

<?php get_header(); ?>

<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>

        <p>index.php updated</p>
        <?php if ( have_posts() ) { while ( have_posts() ) : the_post(); ?>
        <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 -->
        <?php endwhile; } ?>

            <hr>

            <nav>
            <ul class="pager">
                <li><?php next_posts_link('Previous'); ?></li>
                <li><?php previous_posts_link('Next'); ?></li>
            </ul>
            </nav>

            <?php wp_reset_postdata(); ?>

        </article>

        </div><!--col-sm-8 blog-main -->

        <div class="blog-sidebar">

            <?php get_sidebar(); ?>

        </div><!-- /.blog-sidebar -->

    </div> <!--row --> 

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

<div id="scroll-top"><a href="#"><i class="fa fa-chevron-up fa-3x"></i></a></div>

 <?php get_footer(); ?>