Abdul Malik bin Saeed bin Suwaid Ansari says that I heard from Sayyiduna Abu Humaid and Sayyiduna Abu Usaid (may Allah be pleased with them both), they were stating that the Messenger of Allah (peace and blessings be upon him) said: When any one of you enters the mosque, he should recite this supplication: "Allahumma iftah lana abwaba rahmatik" (O Allah! Open for us the doors of Your mercy), and when he leaves the mosque, he should recite: "Allahumma inni as'aluka min fadlik" (O Allah! I ask You for Your bounty).

It is narrated from Sayyidah Fatimah, the daughter of the Messenger of Allah, may Allah be pleased with her and grant her satisfaction, that when the Messenger of Allah, peace and blessings be upon him, would enter the mosque, he would send blessings and peace upon Muhammad, peace and blessings be upon him, and in one narration, he would recite this supplication: "Bismillah, was-salamu ‘ala Rasulillah" (In the name of Allah, and peace be upon the Messenger of Allah), and then he would recite: "Allahumma ighfir li dhunubi waftah li abwaba rahmatik." (O Allah! Forgive my sins and open for me the doors of Your mercy.) And when he, peace and blessings be upon him, would leave, he would send blessings and peace upon Muhammad, peace and blessings be upon him, and in one narration, he would say: "Bismillah, was-salamu ‘ala Rasulillah," and then recite this supplication: "Allahumma ighfir li dhunubi waftah li abwaba fadlik." (O Allah! Forgive my sins and open for me the doors of Your bounty.)

Ubaidullah bin Abdur Rahman bin Muhib narrates from a servant of Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him), who says: I was in the company of Sayyiduna Abu Sa'id (may Allah be pleased with him) with the Messenger of Allah (peace and blessings be upon him), we entered the mosque and saw that a man was sitting cross-legged in the middle of the mosque, intertwining the fingers of his hands. The Messenger of Allah (peace and blessings be upon him) gestured to him, but the man did not understand. Then the Prophet (peace and blessings be upon him) turned to Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) and said: When any of you is in the mosque, he should not intertwine his fingers, because intertwining is from Satan, and indeed as long as a person remains in the mosque, he is considered to be in prayer until he leaves the mosque.

Sayyiduna Ka’b bin ‘Ujrah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) came to me in the mosque while I had interlaced my fingers. He (peace and blessings be upon him) said to me: O Ka’b! When you are in the mosque, do not interlace your fingers, because as long as you are waiting for the prayer, you are considered to be in prayer.

It is narrated from Sayyiduna Abu Musa Ash'ari, may Allah be pleased with him, that the Noble Prophet, peace and blessings be upon him, said: When you pass through the markets of the Muslims or their mosques with arrows, hold them by their tips (the sharp ends), lest you injure someone with them.

It is narrated from Sayyiduna Abu Musa Ash'ari (may Allah be pleased with him) through another chain that the Messenger of Allah (peace and blessings be upon him) said three times: When any one of you passes through the market, a gathering, or a mosque while carrying arrows, he should hold them by their tips. Abu Musa said: Trials kept befalling us until some of us ended up pointing these arrows straight at the faces of others.

Sufyan bin Uyaynah says that I asked Amr bin Dinar, "Did you hear Sayyiduna Jabir bin Abdullah (may Allah be pleased with him) say that a man passed through the mosque with an arrow, so the Noble Prophet (peace and blessings be upon him) said to him: 'Hold them by their tips'?" So Amr said, "Yes! I have heard it."

It is narrated through another chain that Jabir (may Allah be pleased with him) was informed by Sayyiduna Bannah Juhani (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) passed by some people in the mosque or in a gathering who were handing unsheathed swords to each other. Upon seeing this, he (peace and blessings be upon him) said: May Allah curse the one who does this. Did I not forbid you from doing so? When you draw a sword, a person should keep it in its sheath, then hand it over in that manner.

Sayyiduna Abu Hurairah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: When any of you is in the mosque, Satan makes an excuse with him, just as a man makes an excuse with his animal. When he settles it for him, he bends it down or puts a bridle on it. Sayyiduna Abu Hurairah (may Allah be pleased with him) says: You see all this; the one who is bent down, you see him bent in such a way that he does not remember Allah, and the one who is bridled, he opens his mouth and thus does not remember Allah.