Inserting css with php

I’ve added this code to show the featured image hooking in to Above Header. The image will show fine, but not when I try and make it a background image.

This is the code:

<?php $pic = get_the_post_thumbnail( $post_id, $size, $attr );
echo $pic; ?>
<div style="padding:20px; background-color:silver; background-image: url('<?php echo $pic; ?>')">abcdef</div>

Line 2 displays properly.
Line 3 displays ‘)”>abcdef

Any idea why?

https://www.ads-software.com/plugins/genesis-simple-hooks/