During the time of the Prophet (salallahu alayhi wasalam) the kuffar were also afraid of Abu Bakr (radhiallahu anhu)'s praying and reciting the Quran where everyone could see and hear him. The truth is that the followers of shaytaan cannot bear to see anything relating to obedience and worship of Allah.
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Narrated by Aisha Bint Abu Bakr (the wife of the Prophet):
...When the Muslims were put to test (troubled by the pagans), Abu Bakr set out migrating to the land of Abyssinia (Ethiopia), and when he reached Bark-al-Ghimad, Ibn Ad-Daghina, the chief of the tribe of Qara, met him and said, 'O Abu Bakr! Where are you going?' Abu Bakr replied: 'My people have turned me out (of my country), so I want to wander on the earth and worship my Lord.' Ibn Ad-Dhagina said: 'O Abu Bakr! A man like you should not leave his homeland, nor should he be driven out, because you help the destitute, earn their living, and you keep good relations with your kith and kin, help the weak and the poor, entertain guests generously, and help the calamity-stricken persons. Therefore, I am your protector. Go back and worship your Lord in your town.'
"So Abu Bakr returned and Ibn Ad-Daghina accompanied him. In the evening Ibn Ad-Dhagina visited the nobles of Quraish and said to them. 'A man like Abu Bakr should not leave his homeland, nor should he be driven out. Do you (Quraish) drive out a man who helps the destitute, earns their living, keeps good relations with his kith and kin, helps the weak and poor, entertain guests generously and helps the calamity-stricken persons?' So the people of Quraish could not refuse Ibn Ad-Dhagina's protection, and they said to Ibn Ad-Daghina: 'Let Abu Bakr worship his Lord in his house. He can pray and recite there whatever he likes, but he should not hurt us with it, and should not do it publicly, because we are afraid that he may affect our women and children."...
Bukhari, Volume 5, Book 58, Number 245