اللَّهُمَّ افْتَحْ لِي أَبْوَابَ رَحْمَتِكَ
Allahumma-ftah li abwaba rahmatik
Ee Allah, nifungulie milango ya rehema Yako.
Recite when entering the masjid
The Prophet (PBUH) would say this when entering the masjid, asking Allah to open the doors of His mercy.