<?php
$_categories = get_categories( array(
            'orderby' => 'order',
            'order' => 'ASC',
            'include' => array(2,3,4) // put the category IDs here
        ) );

// Loop to display each of the Category
foreach( $_categories as $_category ) :

    $_posts = get_posts( array(
            'posts_per_page' => 6,
            'category__in' => array( $_category->term_id ),
            'ignore_sticky_posts' => 1,
            'post_status' => 'publish'
        ) );

    if( $_posts ) :

        echo '<section id="category-'. intval($_category->term_id) .'" class="category-block">';

            echo '<h1 class="category-title">'. esc_html($_category->name) .'<h1>';

            echo '<div class="category-articles">';

                // Loop to display posts of certain a category
                foreach( $_posts as $post ) : setup_postdata( $post );
                    echo '<article id="post-'. get_the_ID() .'" class="'. join( ' ', get_post_class( '', get_the_ID() ) .'">';
                        echo '<a href="'. get_the_permalink() .'" rel="bookmark">'. get_the_title() .'</a>';
                    echo '</article>';
                endforeach; wp_reset_postdata();

            echo '</div>';

            // A link to the Category archive
            echo '<a href="'. get_category_link( $_category->term_id ) .'" title="'. sprintf( esc_attr__( "View all posts in %s" ), $_category->name ) .'"></a>';

        echo '</section>';

    endif;

endforeach;