اللَّهُمَّ إِنِّي أَسْأَلُكَ الْجَنَّةَ وَأَعُوذُ بِكَ مِنَ النَّارِ
O Allah, I ask You for Paradise and seek Your protection from the Fire.
Allaahumma 'innee 'as'alukal-jannata wa 'a'oothu bika minan-naar.
Abu Dawud 792. See also Al-Albani, Sahih Ibn Majah 2/328