Ask Allah for mercy & grace when entering & exiting the masjid

This hadith is about the importance of asking Allah for mercy and grace when entering or leaving a mosque. The Prophet Muhammad ﷺ taught us that when we enter a mosque, we should say "O Allah! open for me the doors of Thy mercy" as an expression of our faith in Him. Similarly, when we leave the mosque, we should say "O Allah! I beg of Thee Thy Grace" to show our gratitude to Him. This hadith teaches us that it is important to be mindful of God's presence at all times and to express our faith in Him through prayer even during simple activities such as entering or leaving a mosque. It also reminds us that it is important to be thankful for His blessings by expressing gratitude whenever possible.