It is recommended to use miswak before performing salah (prayer). So that your mouth is clean, fragrant and perfect when doing salah.
In a hadith from Abu Hurairah (may Allah blesses him), that the Messenger of Allah (ﷺ) says:
لولا أن أشق على أمتي – أو على الناس- لأمرتهم بالسواك مع كل صلاة
“Had I not thought it difficult for my Ummah, I would have commanded them to use the Miswak (tooth-stick) before every Salah” [al-Bukhari and Muslim].
Our scholar says, using miswak can be replaced also by brushing teeth using toothpaste. Because “siwak” in Arabic means an act of cleaning our mouth. So, every act of cleaning our mouth is called siwak, including tooth brushing.
Using miswak or siwak is sunnah, means is not obligatory. But there will be rewards if you do. In fact, it is one of our forms to follow the teachings of the Prophet (ﷺ).
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