Allah has tested man by giving satan the ability to suggest negative thoughts to him. The influence of his suggestions varies according to the depth of one’s faith. Satan has the most power to influence unbelievers, while he is deprived of authority over believers’ fear of Allah..
He said, ‘My Lord, because You misled me, I will make things on the earth seem good to them and I will mislead them all, every one of them, except Your servants among them who are sincere.’ (Surat al-Hijr; 39-40)
Despite the fact that satan cannot divert true believers from the right path, he may still strive to cause them harm, distract them or make them forget. No doubt, those people who act under the influence of satan disturb believers through their speech and attitudes, numbing their minds and hindering them from engaging in good deeds.
One of the aims of satan is to prevent a Muslim from reading Allah’s words with attention and understanding or putting them into practice in the course of the day. Because Allah guides believers to right conduct through the Qur’an, satan's unique aim is to divert them from it. For this reason, he wants them to fail to properly understand its content and tries to turn them away from the Qur’an.
When faced with the strategies of satan, Allah commands believers to take refuge with Him:
Whenever you recite the Qur’an, seek refuge with Allah from the accursed satan” (Surat an-Nahl; 98)
Those who have faith in Allah and put their trust in Him will be secure from the evil insinuations of satan:
He [satan] has no authority over those who believe and put their trust in their Lord. (Surat an-Nahl; 99)