repeated reading makes the meaning clear
A yojijukugo proverb meaning that reading a difficult text many times will eventually lead to understanding. Often used as encouragement to persevere with study.
Read a book a hundred times, and its meaning will naturally become clear.
Even difficult classics can be understood through repeated reading.
The full proverb form; 読書百遍 is a common abbreviation.
From the Chinese proverb 讀書百遍其義自見 (dú shū bǎi biàn qí yì zì xiàn), meaning 'if you read a book a hundred times, its meaning will appear by itself.' The Japanese form is a direct adaptation.