Dark Side of the Moon

At work, there's a semi-open office/reception area that's being turned into a shared-work space for people who work from home some days but need a place to sit for the days they do come to the office.  The construction started last Friday and will continue all month.   They've hung a big sheet of plastic between the area and the hallway so the rest of us won't be incomvenienced by dust and debris. 

This morning when I passed by, the guys behind the plastic were discussing Islam and Christianity and religion in general... "I don't want a higher power telling me what to do." 

This afternoon when I walked by, they were talking about recipes and restaurants... "Then on the salmon, he puts this..."

In almost any play or movie or TV show or book, they'd be talking about beer & sports & hot chicks instead,  unless the writer was making a specific point and beating the audience over the head with it.   Why?
  
 

"Lilies are not as white, nor roses red"

This line is in one of my sonnets.  Someone has said it's a direct lift from Shakespeare and I apologized and said I'd change it.   But I wanted to find the source first... and I can't.  

Granted, it sounds very familiar.  It's trite, it's overdone, it's hackneyed, it's a cliche, etc.   But is it Shakespeare?  I've tried three different sites that offer searches on Shakespeare's texts.  I've looked for "lilies" near "roses" (where "near" is within 50 words), "roses" near "lilies", "roses", "lilies", "rose", "lily", and "are not" near "nor."    Can't find anything that matches at all closely to both sense and format.   Maybe it's someone other than Shakespeare?  Maybe the searches aren't working?

If anyone can tell me where something like this exists, I'd appreciate it very much, because it's driving me crazy, because the phrase DOES sound so close to something else.