Why trust the Bible?

Psalm 12:6 says “The words of the LORD are flawless, like silver refined in a furnace of clay, purified seven times.”
God’s words (the text of the Bible), is like silver refined seven times

Why not just refined once once?

“Seven” in the Bible is the number for completeness and wholeness.  What Psalm 12:6 is saying is that God’s words are completely pure, without error and wholly reliable.

Yet, there may be more to the number seven: