The term traces to The Venerable Bede, 
an 8th-century
                     Anglo-Saxon scholar, 
historian, and theologian 
who wrote a history of
                     England in which he dated 
events from the birth of Christ. 

Bede's history was
                     translated from Latin to English 
around the year 900, and it is in that
       translated text that 
we find the earliest evidence 
for "holy writ." 

Shakespeare
                     later used "holy writ" in Othello: 
"Trifles light as air are to the jealous
                     confirmations strong as proofs 
of holy writ." 

And Alexander Pope used it in his 
Wife of Bath: 
"And close the sermon, 
as beseem'd his wit, with some
    grave sentence out of holy writ."