اَللَّهُمَّ رَبَّ جِبْرَائِيْلَ وَمِيْكَائِيْلَ وَإِسْرَافِيلَ فَاطِرَ السَّمَوَاتِ وَالْأَرْضِ عَالِمَ الْغَيْبِ وَالشَّهَادَةِ أَنْتَ تَحْكُمُ بَيْنَ عِبَادِكَ فِيمَا كَانُوا فِيهِ يَخْتَلِفُونَ اهْدِنِيْ لِمَا اخْتُلِفَ فِيهِ مِنَ الْحَقِّ بِإِذْنِكَ إِنَّكَ تَهْدِيْ مَنْ تَشَاءُ إِلَى صِرَاطٍ مُسْتَقِيْمٍ

Allaahumma rabba jibra-eel, wameeka-eel, wa-israafeel faatiras-samawaati wal-ardi, AAalimal-ghaybi washshahaadah, anta tahkumu bayna ibaadika feemaa kanoo feehi yakhtalifoon ihdinee limakh-tulifa feehi minal-haqqi bi-idhnika, innaka tahdee man tashaa-o ilaa siraatin mustaqeem

O Allah, Lord of Jibra-eel, Meeka-eel and Israfeel (great angles), Creator of the heavens and the Earth, Knower of the seen and the unseen. You are the arbitrator between Your servants in that which they have disputed. Guide me to the truth by Your leave, in that which they have differed, for verily You guide whom You will to a straight path. Ayesha said, "The Messenger of Allah (ﷺ), used to recite this du'a at the beginning of the night (tahajjud) prayer." It should be noted that every researcher, scholar, mufti and truth-seeking believer should recite this dua more and more at the beginning of tahajjud, in prostration and at all other times. It is very important to seek guidance from Allah Almighty through this dua without relying entirely on one's own research, knowledge or anything else.

Reference: Muslim: 770