Drop this function in your functions.php without the initial <?php if there already is an opening tag in your functions.php.

functions.php

<?php

function ict_bz_render_pages( $args = array(), $template = 'content-page' ) {

	// Default values for the query
	$defaults = array(
		'post_type' => 'page',
		'post_status' => 'publish',
		'order' => 'ASC',
		'orderby' => 'menu_order',
		'posts_per_page' => 500,
	);

	// Merge default args and with the args provided by the function
	$args = wp_parse_args( $args, $defaults );

	// Returns WP_Query|WP_Error
	$page_query = new WP_Query( $args );

	// Fail early if possible
	if ( is_wp_error( $page_query ) )
		return false;

	// See if we have the designated template file in the theme or parent theme
	if ( '' == locate_template( $template . '.php' ) )
		$template = 'content';

	if ( $page_query->have_posts() ) {
		
		while( $page_query->have_posts() ) : $page_query->the_post();
			get_template_part( $template );
		endwhile;

	}

	// Reset the post data set up by WP_Query
	wp_reset_postdata();

}