Du'a to stop Shaytan's whispers

رَّبِّ أَعُوذُ بِكَ مِنۡ هَمَزَٰتِ ٱلشَّيَٰطِينِ وَأَعُوذُ بِكَ رَبِّ أَن يَحۡضُرُونِ

Rabbi a'oodhu bika min hamazaatish-shayaateen, wa a'oodhu bika Rabbi an yahduroon

My Lord! I seek refuge in Thee from suggestions of the evil ones And I seek refuge in Thee, my Lord, lest they be present with me

Qur'an 23:97-98 (Al-Mu'minun)