Tirmidhi

Benefits and Issues:
➊ This narration is weak, and according to some, the wording of «ولا نهار» is not established. (That is, after waking up from sleep, this practice was only done at night.)
➋ There are many benefits of using the miswak, and the greatest benefit is that the miswak is a means of attaining the pleasure of Allah Ta’ala, and it also purifies the mouth, as is narrated from Umm al-Mu’minin Sayyidah Aisha Siddiqa radi Allahu anha, that the Messenger of Allah sallallahu alayhi wa sallam said: «السواك مطهرة للفم مرضاة للرب» [سنن نسائي، حديث : 5] “The miswak purifies the mouth and is a means of the Lord’s pleasure.”
➌ It is as clear as daylight that Allah Ta’ala’s pleasure is attained only by doing those deeds which He loves; therefore, when using the miswak, one should have the intention and resolve that by this, our Allah will be pleased with us. Physicians and doctors have also mentioned many of its benefits.
➍ By using the miswak, impurities of the mouth and throat are abundantly removed and eliminated. The use of the miswak should not be limited only to the teeth, but should be extended to the tongue and up to the area near the throat, especially upon waking up in the morning, it should be done in this manner, because this was the practice of the Messenger of Allah sallallahu alayhi wa sallam. Whenever he sallallahu alayhi wa sallam would wake up from sleep, he would use the miswak, and he would do so thoroughly, to the extent that sounds like ‘Aa Aa’, ‘Uh Uh’, and ‘Ah Ah’ would come from his blessed mouth.
➎ We should keep in mind that the Messenger of Allah sallallahu alayhi wa sallam himself was diligent and consistent in using the miswak, and he also emphasized it to the ummah to the same degree. And if there had not been a fear of hardship and burden upon the ummah, he sallallahu alayhi wa sallam would have made it obligatory at every ablution (wudu) and at every prayer.
➏ The Messenger of Allah sallallahu alayhi wa sallam did not like even the slightest odor from the mouth; that is why, upon waking up from sleep, he would immediately use the miswak.

Hadith Commentary: Benefits and Issues: Various forms of the night prayer (tahajjud) are established from the Messenger of Allah sallallahu alayhi wa sallam. His general practice was that he would perform eleven rak‘ahs including witr, but at times, due to being occupied, illness, sleep, or difficulty, he made additions or reductions in this.

In his later years, due to old age, he sallallahu alayhi wa sallam also reduced the number. Therefore, from him sallallahu alayhi wa sallam, seven, nine, eleven, and thirteen rak‘ahs are established. Hafiz Ibn Qayyim rahimahullah has mentioned eight forms of the Prophet’s sallallahu alayhi wa sallam night prayer.

He sallallahu alayhi wa sallam sometimes performed only one witr at the end. According to Imam Malik rahimahullah, Imam Shafi‘i rahimahullah, and Imam Ahmad rahimahullah, the better method is to perform a single witr at the end. And the Prophet sallallahu alayhi wa sallam also performed three witr with one salam, without sitting in between, and five as well, in which he sallallahu alayhi wa sallam sat only in the fifth rak‘ah. He also performed seven witr, in which he sallallahu alayhi wa sallam sat in the sixth rak‘ah but made salam after sitting in the seventh rak‘ah. In this way, he performed nine witr, sitting in the eighth rak‘ah and making salam in the ninth rak‘ah. All these forms are permissible.

According to the Hanafis, there is only one form of witr: that witr is three rak‘ahs and they are to be performed with two tashahhuds like Maghrib. However, in the narration of Sahih Ibn Hibban rahimahullah, which Imam Hakim rahimahullah, Imam Dhahabi rahimahullah, and Imam Bayhaqi rahimahullah have declared authentic, this form has been prohibited.