اللَّهُمَّ افْتَحْ لِي أَبْوَابَ رَحْمَتِكَ
Purpose Ask Allah to open the doors of His mercy.
When to Use Read this when entering a masjid.
Source Sahih Muslim

Transliteration

Allahumma iftah li abwaba rahmatik.

Meaning

O Allah, open for me the doors of Your mercy.