Sunan Abi Dawud Book 2, Hadith 62
The pillars of the mosque of the Prophet (ﷺ) during the life time of the Messenger of Allah (ﷺ) were made of the trunks of the palm-tree; they covered from the above by twigs of the palm-tree; they decayed during the caliphate of Abu Bakr. He built it afresh with trunks and twigs of the palm-tree. But they again decayed during the caliphate of 'Uthman. He, therefore, built it with bricks. That survives until today.
The mosque (of the Prophet) during his lifetime was built with bricks, its roof with branches of the palm-tree, and its pillars with palm-wood, as Mujahid said: Abu Bakr did not add anything to it. But 'Umar added to it; he built as it was built during the lifetime of the Messenger of Allah (ﷺ) with bricks and branches, and he changed its pillars. Mujahid said: Its pillars were made of wood. 'Uthman changed it altogether with increasing addition. He built its walls with decorated stone and lime. And he built the pillars with decorated stone and its roof with teak. Mujahid said: Its roof was made of teak.
Abu Dawud said: Al-Qassah means lime used as mortar.
Messenger of Allah (ﷺ) came over to Medina and encamped at the upper side of Medina among the tribe known as Banu 'Amr b. 'Awf. He stayed among them for fourteen days. He then sent someone to call Banu al-Najjar. They came to him hanging their swords from the necks. Anas then said: As if I am looking at the Messenger of Allah (ﷺ) sitting on his mount and Abu Bakr seated behind him, and Banu al-Najjar standing around him. He descended in the courtyard of Abu Ayyub. The Messenger of Allah (ﷺ) would say his prayer in the folds of the sheep and goats. He commanded us to build a mosque. He then sent for Banu al-Najjar and said to them: Banu al-Najjar, sell this land of yours to me for some price. They replied: By Allah, we do not want any price (from you) except from Allah. Anas said: I tell what this land contained. It contained the graves of the disbelievers, dung-hills, and some trees of date-palm. The Messenger of Allah (ﷺ) commanded and the graves of the disbelievers were dug open, and the trees of the date-palm were cut off. The wood of the date-palm were erected in front of the mosque ; the door-steps wre built of stone. They were reciting verses carrying the stones. The Prophet (ﷺ) also joined them (in reciting verses) saying: O Allah, there is no good except the good of the Hereafter. So grant you aid to the Ansar and the Muhajirah.