Reference : Hisn al-Muslim 118

اللّهُـمَّ إِيّـاكَ نعْـبُدْ،
وَلَـكَ نُصَلّـي وَنَسْـجُد،
وَإِلَـيْكَ نَسْـعى وَنَحْـفِد،
نَـرْجو رَحْمَـتَك،
وَنَخْشـى عَـذابَك،
إِنَّ عَـذابَكَ بالكـافرين ملْحَـق.
اللّهُـمَّ إِنّا نَسْتَعـينُكَ
وَنَسْتَـغْفِرُك، 
وَنُثْـنـي عَلَـيْك الخَـيْرَ،
وَلا نَكْـفُرُك،
وَنُـؤْمِنُ بِك، 
وَنَخْـضَعُ لَكَ
وَنَخْـلَعُ مَنْ يَكْـفرُك
Allāhumma iyyāka na`bud, 
wa laka nuṣallī wa nasjud, 
wa ilayka nas`ā wa naḥfid, 
narjū raḥmatak, 
wa nakhshā `adhābak, 
inna `adhābaka bilkāfirīna mulḥaq. 
Allāhumma innā nasta`īnuk, 
wa nastaghfiruk, 
wa nuthnī `alaykal-khayr, 
wa lā nakfuruk, 
wa nu'minu bik, 
wa nakhḍa`u lak, 
wa nakhla`u man yakfuruk.


O Allah, You alone do we worship,
and to You we pray and bow down prostrate. 
To You we hasten to worship and to serve.
Our hope is for Your mercy,
and we fear Your punishment. 
Surely, Your punishment of the disbelievers is at hand. 
O Allah, we seek Your help and Your forgiveness, 
and we praise You beneficently. 
We do not deny You and we believe in You. 
We surrender to You 
and renounce whoever disbelieves in You.

Reference:
Al-Bayhaqi graded its chain authentic in As-Sunan Al-Kubra. Al-Albani said 
in 'Irwa'ul-GhaliL 2/170 that its chain is authentic as a statement of 
'Umar.

Chapter: Qunoot Al-Witr