﴿ لَا تَقُمْ فِيهِ أَبَدًۭا ۚ لَّمَسْجِدٌ أُسِّسَ عَلَى ٱلتَّقْوَىٰ مِنْ أَوَّلِ يَوْمٍ أَحَقُّ أَن تَقُومَ فِيهِ ۚ فِيهِ رِجَالٌۭ يُحِبُّونَ أَن يَتَطَهَّرُوا۟ ۚ وَٱللَّهُ يُحِبُّ ٱلْمُطَّهِّرِينَ ﴾

“Never set foot in such a place! Only a house of worship founded, from the very first day, upon God-consciousness is worthy of thy setting foot therein -[a house of worship] wherein there are men desirous of growing in purity: for God loves all who purify themselves.”

(Never stand (to pray) there) never pray in the mosque of opposition. (A place of worship) i.e. the mosque of Quba' (which was founded upon duty (to Allah)) which was founded upon obedience and remembrance of Allah (from the first day) the Prophet (pbuh) entered Medina; it is also said this means: the first mosque ever built in Medina (is more worthy) is more right (that thou shouldst stand (to pray) therein) in the mosque of Quba', (wherein are men who love to purify themselves) men who wash their behinds with water [after defecating]. (Allah loveth the purifiers) those who purify themselves from filth with water.