It is narrated from Sayyiduna Muhajir bin Qunfudh bin ‘Amr bin Jud‘an (may Allah be pleased with him) that he came to the Prophet Muhammad (peace and blessings be upon him) while he was performing ablution. He greeted the Prophet with salam, but the Messenger of Allah (peace and blessings be upon him) did not reply to his salam until he had completed his ablution (and then replied to the salam). He apologized for this and said: "I disliked mentioning Allah without being in a state of purity." Hasan al-Basri (may Allah have mercy on him) used to act according to this hadith, that is, he would reply to salam only when in a state of ablution.

It was because mentioning Allah Almighty with purity is more virtuous, not because mentioning Allah Almighty without purity is not permissible. Because the Prophet Muhammad (peace be upon him) used to mention Allah Almighty at all times.

Lady Aisha (may Allah be pleased with her) narrates that the Messenger of Allah (peace be upon him) used to remember Allah Almighty at all times. These are the words of Abu Kurayb’s narration.

Hazrat Amr bin Murrah (may Allah have mercy on him) says that I heard Hazrat Abdullah bin Salamah (may Allah have mercy on him) say: I and other people went to Sayyiduna Ali (may Allah be pleased with him). One man was from us (i.e., from our tribe) and one was from Banu Asad. I think he sent both of them in one direction (as governors or officials of a region) and said: Both of you are healthy and strong, so fulfill your duty well. Then he entered the toilet, and after relieving himself, he came out, took a handful of water and washed his hands, then came to us and recited some verses of the Holy Qur’an. We disliked it, so Sayyiduna Ali (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) used to enter the toilet and relieve himself, then come out, and our companions would eat bread and meat and recite the Holy Qur’an, and nothing except major impurity (janabah) would prevent the Prophet (peace and blessings be upon him) from reciting the Qur’an. Imam Abu Bakr (may Allah have mercy on him) has also narrated this hadith from Imam Shu’bah (may Allah have mercy on him). Imam Shu’bah (may Allah have mercy on him) says: This hadith is one third of my original wealth (i.e., knowledge). Imam Abu Bakr (may Allah have mercy on him) says: I have already explained in Kitab al-Buyu’ that there is a difference between makruh (disliked) and haram (forbidden). I have taken evidence for the difference between the two from this statement of the Prophet (peace and blessings be upon him): «‏‏‏‏ان الله كره لكم ثلاثا و حرم عليكم ثلاثا...» ‏‏‏‏ Allah Almighty has disliked three things for you and has declared three things forbidden for you. He has disliked for you idle talk, excessive questioning, and wasting wealth. He has forbidden you to disobey your mothers, to bury your daughters alive, and to be miserly and greedy. In the hadith of Muhajir bin Qunfudh, the Prophet (peace and blessings be upon him) differentiated between makruh and haram by his statement: «‏‏‏‏كرهت ان اذكر الله على طهر» ‏‏‏‏ (I disliked mentioning Allah without being in a state of purity.) It is possible that the Prophet (peace and blessings be upon him) disliked it because mentioning Allah in a state of purity is better, not because it is forbidden to mention Him without purity, because the Prophet (peace and blessings be upon him) used to recite the Qur’an without being in a state of purity, and reciting the Qur’an is the best form of remembrance (dhikr), and the Prophet (peace and blessings be upon him) used to remember Allah in every state, as we have been told in the hadith of Sayyidah Aisha (may Allah be pleased with her). It is also possible that the Prophet (peace and blessings be upon him) considered it makruh to remember Allah without wudu because that remembrance refers to the remembrance that is obligatory on a Muslim, not the voluntary one. And the obligatory remembrance of Allah cannot be performed without purity; rather, it should be performed after attaining purity. Because according to most scholars, replying to salam is obligatory, and that is why the Messenger of Allah (peace and blessings be upon him) did not reply to salam without being in a state of purity, until he attained purity and then replied to salam. But if a person is engaged in voluntary remembrance and leaves it in a state of impurity, then it is not necessary for him to repeat that remembrance. Therefore, it is permissible for him to do voluntary remembrance even if he is not pure (with wudu).

Sayyiduna Ali bin Abi Talib (may Allah be pleased with him) narrates that we set out with the Messenger of Allah (peace and blessings be upon him) until when we reached the rocky black land of Sayyiduna Sa’d bin Abi Waqqas (may Allah be pleased with him) at the place of Suqya, the Messenger of Allah (peace and blessings be upon him) said:“Bring water for me to perform ablution.”Then when he had performed ablution, he faced the Qiblah and stood, then he said «‏‏‏‏اللهُ أَكْبَرُ» ‏‏‏‏ and then he said «‏‏‏‏أبِي إِبْرَاهِيمُ كَانَ عَبْدُكَ وَخَلِيلُكَ، وَدَعَاكِ لِأهْلِ مؐكّةَ وَأَنَا مُحَمَّدٌ، عَبْدُكَ وَرَسُوْلُكَ، أَدْعُوكَ لِأَهْلِ الْمَدِينَةِ أَنْ تَبَارَكْ لَهُمْ فِي مُدِّهِمْ وَصَاعِهِمْ مِثْلَ مَا بَارَكْتَ لِأَهْلِ مَكَّةَ مَعَ الْبَرَكَةِ بَرَكَتَيْنِ» ‏‏‏‏“(O Allah) my father Ibrahim was Your servant and Your close friend, and he prayed to You for the people of Makkah, and I, Muhammad, am Your servant and Messenger, I pray to You for the people of Madinah that You grant them blessing in their mudd and sa’ just as You granted blessing to the people of Makkah. Grant blessing with two blessings.”

Sayyiduna Abu Qatadah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) performed ablution, then offered prayer in the land of Sayyiduna Sa’d (may Allah be pleased with him). Then the rest of the incident was narrated.

It is narrated from Sayyiduna Umar (may Allah be pleased with him) that he asked the Messenger of Allah (peace and blessings be upon him), "Can any one of us sleep in a state of janabah (major ritual impurity)?" The Prophet (peace and blessings be upon him) said: "He can sleep, and if he wishes, he may perform ablution."

It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that Sayyiduna Umar (may Allah be pleased with him) asked the Messenger of Allah (peace and blessings be upon him), "Can any one of us sleep in a state of janabah (major ritual impurity)?" The Prophet (peace and blessings be upon him) said: "When he intends to sleep, he should perform ablution."

Lady Aisha (may Allah be pleased with her) narrates that when the Messenger of Allah (peace and blessings be upon him) intended to sleep in a state of major ritual impurity (janabah), he would perform ablution (wudu) as he did for prayer.

Hazrat Abdullah bin Dinar (may Allah have mercy on him) says that I heard Sayyiduna Ibn Umar (may Allah be pleased with them both) saying that Sayyiduna Umar (may Allah be pleased with him) asked the Messenger of Allah (peace and blessings of Allah be upon him): "I become junub (in a state of major ritual impurity) at night, so what should I do?" The Prophet (peace and blessings of Allah be upon him) said: "Wash your private parts and perform wudu, then go to sleep."