John 5:47

But if ye believe not his writings, how shall ye believe my words?
— John 5:47, King James Version

In other translations

World English Bible (WEB)

But if you don't believe his writings, how will you believe my words?"

American Standard Version (ASV)

But if ye believe not his writings, how shall ye believe my words?

Young's Literal Translation (YLT)

but if his writings ye believe not, how shall ye believe my sayings?'