The use of Miswak is a means of purifying the mouth and is pleasing to Allah (The Exalted).
Sunnah of All The Prophet’s (upon them all be peace)
The Miswak is a stick by which a person cleans the mouth. This is a great Sunnah of the Messenger of Allah (may Allah bless him and grant him peace). It is also a Sunnah of all the Messengers of Allah (upon them all be peace), for they used the Miswak.
Abu Ayyub Ansari (may Allah be pleased with him) narrates that four things are the Sunnahs of all the prophets (upon them all be peace) 1) Circumcision, 2) To apply fragrance (Itr), 3) To use Miswak, 4) Marriage.