Dua at the start of prayer after takbeer

اللّهُـمَّ رَبَّ جِـبْرائيل ، وَميكـائيل ، وَإِسْـرافيل، فاطِـرَ السَّمواتِ وَالأَرْض ، عالـِمَ الغَيْـبِ وَالشَّهـادَةِ أَنْـتَ تَحْـكمُ بَيْـنَ عِبـادِكَ فيـما كانوا فيهِ يَخْتَلِفـون. اهدِنـي لِمـا اخْتُـلِفَ فيـهِ مِنَ الْحَـقِّ  بِإِذْنِك ، إِنَّـكَ تَهْـدي مَنْ تَشـاءُ إِلى صِراطٍ مُسْتَقـيم

‘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.’ [Sunan an-Nasa’i 1625]

اللّهُـمَّ O Allah

رَبَّ جِـبْرائيل وَميكـائيل وَإِسْـرافيل Lord of Gibraeel, Mikaeel, and Israfeel

فاطِـرَ Creator (Root ف ط ر Page 802 in Quran Dictionary)

السَّمواتِ the heavens

وَالأَرْض and earth

، عالـِمَ Knower

الغَيْـبِ (of) unseen

وَالشَّهـادَةِ and seen

أَنْـتَ You

تَحْـكمُ judge

بَيْـنَ between

عِبـادِكَYour slaves

فيـما in what

كانوا they are

فيهِ in it

يَخْتَلِفـون disputing ( Root word خ ل ف Page 532)

اهدِنـي guide me

لِمـا to what

اخْتُـلِفَ they disputed ( Root word خ ل ف Page 532)

فيـهِ in it

مِنَ الْحَـقِّ from the truth 

بِإِذْنِك with Your permission

، إِنَّـكَ indeed

تَهْـدي You guide

مَنْ who

تَشـاءُ You will

إِلى to

صِراطٍ path

مُسْتَقـيم straight