Deuteronomy 27:8
"And thou shalt write upon the stones all the words of this law very plainly."
Cross References (ranked by relevance)
Habakkuk 2:2
And the LORD answered me, and said, Write the vision, and make it plain upon tables, that he may run that readeth it.
John 16:25
These things have I spoken unto you in proverbs: but the time cometh, when I shall no more speak unto you in proverbs, but I shall shew you plainly of the Father.
2 Corinthians 3:12
Seeing then that we have such hope, we use great plainness of speech: