When a Muslim enters a mosque, it is best to recite the dua upon entering the mosque. Man is inherently weak and dependent on the blessings of Allah (سُبْحَانَهُ وَتَعَالَى). Reciting the dua given below is an effective and easy way of gaining the mercy of Allah (سُبْحَانَهُ وَتَعَالَى) and thereby helping oneself to stay on the true path.
The dua to be recited upon entering the mosque is a sunnah and has been verified by multiple hadiths. A hadith by Sahih Muslim (713 a) states that the person who recites the dua for entering the mosque regularly their sins will be forgiven, and they will be the recipient of the everlasting and limitless mercy of Allah (سُبْحَانَهُ وَتَعَالَى). The same has been reported by Fatima (رَضِيَ ٱللَّٰهُ عَنْهَا) in (Sunan Ibn Majah 771), Abu Humaid As-Sa'idi (رَضِيَ ٱللَّٰهُ عَنْهُ) in (Sunan Ibn Majah 772) and by Abu Hurairah (رَضِيَ ٱللَّٰهُ عَنْهُ) in (Sunan Ibn Majah 773).
The dua upon entering the mosque wipes away the sins of the reciter and is an excellent way of asking Allah (سُبْحَانَهُ وَتَعَالَى) for his mercy (Sunan an-Nasa'i 729). The gates of mercy are opened for the person who recites the dua upon entering the mosque (Sunan Abi Dawud 465).
Prayer Duas
'A'oothu billaahil-'Adheem, wa bi-Wajhihil-Kareem, wa Sultaanihil-qadeem, minash-Shaytaanir-rajeem. Bismillaahi, wassalaatu. Wassalaamu 'alaaRasoolillaahi. Allaahum-maftah lee 'abwaaba rahmatika.
I seek refuge in Almighty Allah, by His Noble Face, by His primordial power, from Satan the outcast. In the Name of Allah, and blessings and peace be upon the Messenger of Allah. O Allah, open before me the doors of Your mercy.
Upon entering the mosque, the dua should be recited while placing one's right foot inside the mosque first. Islamic customs demand that a person must start a good deed by their right hand or foot. The same is verified by the sunnah of the Prophet Muhammad( ﷺ ) and his companions. Secondly, the dua should be recited with utmost sincerity with full hope of receiving the blessings and mercy of Allah (سُبْحَانَهُ وَتَعَالَى) and one's sins being forgiven.
Reciting the dua upon entering the mosque is a simple act, yet carries a great reward – Allah has promised to erase the sins of the person who recites this dua. In addition, the person becomes entitled to the mercy of Allah (سُبْحَانَهُ وَتَعَالَى), and the gates of mercy are opened for him. The dua is also a great way of increasing one's good deeds and, at the same time, reminding oneself of the love of Allah (سُبْحَانَهُ وَتَعَالَى) for His creation.