If Job’s friends were wrong, were they blaspheming?

The words found in Job (or any book of the Bible) are scripture, meaning they are inspired by the Lord:

2Tim. 3:16 All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness;

Therefore, we do not sin when we repeat or quote words of scripture. On the contrary, we are honoring God by meditating on His word:

Psa. 119:147      I rise before dawn and cry for help; 
I wait for Your words.
Psa. 119:148      My eyes anticipate the night watches, 
That I may meditate on Your word.

Of course, proper use of scripture requires that we keep any quote in its context so that it can be understood as God intended. In the case of Job's counselors, we may reference their words as example of the foolish things the ungodly will say about God. 

Scripture quotations taken from the (NASB®) New American Standard Bible®, Copyright © 1995, 2020 by The Lockman Foundation. Used by permission. All rights reserved. www.lockman.org