O Allah, unite the Muslims and bring their hearts together. — The Ummah
اللَّهُمَّ اجْمَعْ شَمْلَ الْمُسْلِمِينَ وَأَلِّفْ بَيْنَ قُلُوبِهِمْ
Transliteration: Allaahummajma' shamla al-muslimeena wa allif bayna quloobihim
Translation: O Allah, unite the Muslims and bring their hearts together.
Reference: General supplication