At-Tawbah 9:108

<h2>Masjid Ad-Dirar and Masjid At-Taqwa</h2><p>The reason behind revealing these honorable Ayat is that before the Messenger of Allah ﷺ migrated to Al-Madinah, there was a man from Al-Khazraj called "Abu `Amir Ar-Rahib (the Monk)." This man embraced Christianity before Islam and read the Scriptures. During the time of Jahiliyyah, Abu `Amir was known for being a worshipper and being a notable person among Al-Khazraj. When the Messenger of Allah ﷺ arrived at Al-Madinah after the Hijrah, the Muslims gathered around him and the word of Islam was triumphant on the day of Badr, causing Abu `Amir, the cursed one, to choke on his own saliva and announce his enmity to Islam. He fled from Al-Madinah to the idolators of Quraysh in Makkah to support them in the war against the Messenger of Allah ﷺ. The Quraysh united their forces and the bedouins who joined them for the battle of Uhud, during which Allah tested the Muslims, but the good end is always for the pious and righteous people. The rebellious Abu `Amir dug many holes in the ground between the two camps, into one of which the Messenger fell, injuring his face and breaking one of his right lower teeth. …

Never stand (to pray) there. A place of worship which was found upon duty (to Allah) from the first day is more worthy that thou shouldst stand (to pray) therein, wherein are men who love to purify themselves. Allah loveth the purifiers.

Never stand thou forth therein. There is a mosque whose foundation was laid from the first day on piety; it is more worthy of the standing forth (for prayer) therein. In it are men who love to be purified; and Allah loveth those who make themselves pure.

Never stand you therein. Verily, the mosque whose foundation was laid from the first day on piety is more worthy that you stand therein (to pray). In it are men who love to clean and to purify themselves. And Allah loves those who make themselves clean and pure (i.e. who clean their private parts with dust [i.e. to be considered as soap) and water from urine and stools, after answering the call of nature].

Do not stand in it, ever. A mosque founded upon piety from the first day is worthier of your standing in it. In it are men who love to be purified. God loves those who purify themselves.