اللَّهُمَّ افْتَحْ لِي أَبْوَابَ رَحْمَتِكَ
Allahumma-ftah li abwaba rahmatik
Ó Allah, abre-me as portas da Tua misericórdia.
Recite when entering the masjid
The Prophet (PBUH) would say this when entering the masjid, asking Allah to open the doors of His mercy.