What is the meaning of the bible verse “Do not be overly righteous nor be overly wise: why should you destroy yourselves?� (Ecclesiastes 7:16)?

It means we should be moderate in all things, because if, for example you exaggerate in your religious life by increasing the number of prostrations you do ..etc.. it can lead to pride, and thereby harm you instead of doing you good

This Q&A was found on Archangel Michael & St Bishoy Coptic Orthodox Church : http://www.stbishoy.org.au/modules/smartfaq/faq.php?faqid=35