In the film Harry Potter and Order of the Phoenix, Arthur Weasley leads #HarryPotter through the Ministry of Magic to face his trial. His departing words for the young wizard is: "The truth will out". It just so happens that this last bit of encouragement paraphrases the great William Shakespeare!
As fans know, the wizarding world is separate and hidden from the Muggle world with the aid of magical barriers and memory-erasing spells. Very few wizards have, and even show, an active interest in non-magical folk - except for Arthur Weasley. While many other characters may tolerate Muggles and their magical children, he has a special and rare kind of Muggle sympathy.
The biggest curiosity with this small scene is not only the origin of how he discovered Shakespeare but the use of the line intended in the film.
Firstly, for those who may not have read the books, the purpose of Weasleys' job in the Misuse of Muggle Artefacts Office department is to regulate magic on Muggle objects and attempt to keep items away from Muggles that had been bewitched. We assume a great deal of his work specifically is intended to hide Dark magic or prevent evil intentions committed against Muggles as best as possible. What kind of raid or investigation would lead Weasley to a book about Shakespeare or the Merchant of Venice? How would a witch or wizard bewitch a book against a Muggle? It's a peculiar thing to imagine, indeed.
Secondly, to examine the phrase he uses, it originates from The Merchant of Venice. Lancelot is speaking with Old- Gobbo, his semi-blind father who cannot recognize him. With a great level of certainty, Lancelot is promising that the identity of Gobbo's son will be revealed eventually. Lancelot is convinced of this revelation because he is him; he is that very son.
The ginger-haired Weasley clan considers "the Chosen One" Potter to be like one of their own. Since this line is not in the books, and taking it into context of the scene, Weasley is convinced of Harry's innocence. The Weasleys are quite the optimistic folk as well. Could this insinuate that somehow he is the blind to the power and corruption of the Ministry? He is aware, or hopeful, that in spite of all efforts the Ministry conceals, the truth of Voldemort's return (even Harry's defensive actions taken against Dudley when Dementors attacked them), will come out one way or another.
One clue in the film offers more than what we may consider at face-value about Weasley and other Muggle Sympathizers. As a low-priority employee, who is deemed so unimportant that higher-ups won't even provide a window for his broom-cupboard sized office, Weasley's passion actually allows for much more depth. Beyond the limited scope of purebloods who believe magic has it all, other wizards and witches are opened up to much more rich and vivid culture humans have created.
What other kinds of Muggle culture did Weasley enjoy? Can we assume one step further to think that beyond literature, somewhere in the stacks of his collections he dared tried not to toy with such a contraption like a computer? Or that he had a vintage television and used his wand to fix the broken celluloid of a VHS tape to watch a classic film over and over again? It is a fun idea to consider how much Muggle Sympathizers knew and appreciate our culture.
The script was written by Michael Goldberg, and this line is not included in the original fifth book authored by J.K. Rowling. We may assume that the British wizarding world might have heard of Shakespeare, or that he was in some way magical himself, or simply that Weasley happened to come across his works. Or perhaps believing one step further, as J.K. Rowling has expressed by her body work, words are an inexhaustible source of magic. Through Weasley's singular expression of Muggle admiration, we can even accept that not even the barrier of two worlds can set a limit on them.