When the Prophet ﷺ feared a (group of) people, he would say: "O Allah, we make Thee our shield against them, and take refuge in Thee from their evils." (Using translation from Abū Dāʾūd 1537)   

أَنَّ نَبِيَّ اللهِ ﷺ كَانَ إِذَا خَافَ قَوْمًا قَالَ «اللهُمَّ إِنَّا نَجْعَلُكَ فِي نُحُورِهِمْ وَنَعُوذُ بِكَ مِنْ شُرُورِهِمْ»  

[Machine] I heard the Prophet ﷺ say on the day of the trench: "O Allah, revealer of the Book, swift in account, disperser of clouds, defeat them and shake them."  

سَمِعْتُ النَّبِيَّ ﷺ يَوْمَ الْخَنْدَقِ يَقُولُ «اللهُمَّ مُنَزِّلَ الْكِتَابِ سَرِيعَ الْحِسَابِ مُجْرِيَ السَّحَابِ اهْزِمْهُمْ وَزَلْزِلْهُمْ»  

[Machine] That the Messenger of Allah ﷺ used to move his lips after the Fajr prayer on the days of Hunayn. So they said, "O Messenger of Allah, you move your lips with something?" He said, "Indeed, a prophet from among those before you mentioned a word that his ummah (nation) admired the abundance of. So he said, 'None of these people will underestimate anything.' So Allah inspired to him to choose for his nation one of three options: to unleash upon them an enemy from among themselves who will take them as captives, or to inflict them with hunger, or to send death upon them.' So they said, 'As for hunger and the enemy, we cannot endure them. But as for death, send death upon them.' So seventy thousand of them died in one night. And I say, 'O Allah, it is with You that I strive, it is with You that I compete, and it is with You that I fight.'"  

أَنَّ رَسُولَ اللهِ ﷺ كَانَ يُحَرِّكُ شَفَتَيْهِ أَيَّامَ حُنَيْنٍ بَعْدَ صَلَاةِ الْفَجْرِ فَقَالُوا يَا رَسُولَ اللهِ «إِنَّكَ تُحَرِّكُ شَفَتَيْكَ بِشَيْءٍ؟» قَالَ إِنَّ نَبِيًّا مِمَّنْ كَانَ قَبْلَكُمْ ثُمَّ ذَكَرَ كَلِمَةً مَعْنَاهَا أَعْجَبَتْهُ كَثْرَةُ أُمَّتِهِ فَقَالَ لَنْ يَرُومَ هَؤُلَاءِ أَحَدٌ بِشَيْءٍ فَأَوْحَى اللهُ إِلَيْهِ أَنَّ خَيِّرْ أُمَّتَكَ بَيْنَ إِحْدَى ثَلَاثٍ أَنْ أُسَلِّطَ عَلَيْهِمْ عَدُوًّا مِنْ غَيْرِهِمْ فَيَسْتَبِيَحَهُمْ وَإِمَّا أَنْ أُسَلِّطَ عَلَيْهِمُ الْجُوعَ وَإِمَّا أَنْ أُرْسِلَ عَلَيْهِمُ الْمَوْتَ؟ فَقَالُوا «أَمَّا الْجُوعُ وَالْعَدُوُّ فَلَا طَاقَةَ لَنَا بِهِمَا وَلَكِنَّ الْمَوْتَ فَأُرْسِلَ عَلَيْهِمُ الْمَوْتُ فَمَاتَ مِنْهُمْ فِي لَيْلَةٍ سَبْعُونَ أَلْفًا» فَأَنَا أَقُولُ «اللهُمَّ بِكَ أُحَاوِلُ وَبِكَ أُصَاوِلُ وَبِكَ أُقَاتِلُ»