Because Satan will try to deter us from the right path and from reciting the Quran and anything good that we intend to do. But he cannot harm nor deter us from the right path as long as we put our trust in Allah Almighty and we seek refuge in Him.
Almighty Allah says: ( So when you recite the Qur’an, [first] seek refuge in Allah from Satan, the expelled [from His mercy] .He certainly has no authority over those who believe and put their trust in their Lord.) [An-Nahl 16: 98-99]
لأن الشيطان يحاول أن يوسوس للإنسان و يصرفه عن أي عمل خير. فإذا استعاذ الإنسان من الشيطان الرجيم يعني أنه يلجأ إلى الله تعالى أن يساعده على الوقاية من شر الشيطان.
( فَإِذَا قَرَأۡتَ ٱلۡقُرۡءَانَ فَٱسۡتَعِذۡ بِٱللَّهِ مِنَ ٱلشَّيۡطَـٰنِ ٱلرَّجِيمِ (٩٨) إِنَّهُ ۥ لَيۡسَ لَهُ ۥ سُلۡطَـٰنٌ عَلَى ٱلَّذِينَ ءَامَنُواْ وَعَلَىٰ رَبِّهِمۡ يَتَوَڪَّلُونَ)