Malik related to me from Abd ar-Rahman ibn Harmala that Said ibn al-Musayyab heard the Messenger of Allah ﷺ say, "Shaytan concerns himself with one and two. When there are three, he does not concern himself with them."

وَحَدَّثَنِي مَالِكٌ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ حَرْمَلَةَ، عَنْ سَعِيدِ بْنِ الْمُسَيَّبِ، أَنَّهُ كَانَ يَقُولُ قَالَ رَسُولُ اللَّهِ ﷺ " الشَّيْطَانُ يَهُمُّ بِالْوَاحِدِ وَالاِثْنَيْنِ فَإِذَا كَانُوا ثَلاَثَةً لَمْ يَهُمَّ بِهِمْ " .