Quran speaks to the heart and this will be even manifested in the heart of a disbiliever
During the Makkan period of teaching, when the quran was recited in the Kaba, the disbelievers would make all sort of loud noises in disrespect so that even the genuine listener will not be able to hear.
They were thinking of creating a situaion by which no one will hear the message and will not accept the faith.
However, there was an interesting event happened. One day, Prophet (SAWS) went in to the Holy Sanctury where there was a large group of Quraish polytheists, including the nobles and elders among them.
Unexpectedly, Prophet (SAWS) started reciting the Quran Surah of An-Najm melodiously.
The group heard the recitation, they were stunned by its words. They forgot it was Quran being read, the message struck their heart and they were spellbound.
When the Prophet(SAWS) reached the magnificient ending:
“So fall down in prostration to Allah and worship Him!”
The group fell on prostration themselves in a helpless state. The truth had struck their heart and their conscience admitted it without their will.
When other disbelievers heard, instead of taking lesson, they blamed and accused the former group severly. So, the former group started blaming the Prophet(SAWS) and made lame execuses on what happened to them and kept on going with their plot.
This incident is much relevant in modern days as well. Some of the prominent scholars of today are not born in a Muslim family, because they identified the truth to their heart. Thus Quran is still speaking to the heart doing wonders.
Some of the people who create mischief in the modern times also has identifed the truth but deciding not to believe, they keep on misinterpreting Quran Surahs and Hadith, just the way pagans used to make loud noises.If they did not identify, why would they misinterpret?! They get misled and mislead others.
However, Islam kept winning from its original days and it is still winning and the triump will continue as long as the Almighty decides.