ENOfficial
'Auf b. Malik reported God's messenger as saying, "God will not cause two swords to smite this people together, one from among itself and one from its enemy." Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ عَوْفِ بْنِ مَالِكٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: " لَنْ يَجْمَعَ اللَّهُ عَلَى هَذِهِ الْأُمَّةِ سَيْفَيْنِ: سَيْفًا مِنْهَا وسَيفاً منْ عدُوِّها " رَوَاهُ أَبُو دَاوُد
sunnah.com