The Quran

ما كانَ لِلمُشرِكينَ أَن يَعمُروا مَساجِدَ اللَّهِ شاهِدينَ عَلىٰ أَنفُسِهِم بِالكُفرِ ۚ أُولٰئِكَ حَبِطَت أَعمالُهُم وَفِي النّارِ هُم خالِدونَ

Muhammad Asad

IT IS NOT for those who ascribe divinity to aught beside God to visit or tend¹ God's houses of worship, the while [by their beliefs] they bear witness against themselves that they are denying the truth. It is they whose works shall come to nought, and they who in the fire shall abide!²

In its transitive form, the verb 'amara comprises the meanings of both visiting and maintaining a place; hence my rendering of an ya'muru as "that they should visit or tend".
Some of the commentators conclude from this verse that "those who ascribe divinity to aught beside God" are not allowed to enter mosques ("God's houses of worship"). This conclusion, however, is entirely untenable in view of the fact that in 9 H. - that is, after the revelation of this surah - the Prophet himself lodged a deputation of the pagan Band Thaqif in the mosque at Medina (Razi). Thus, the above verse expresses no more than the moral incongruity of the unbelievers' "visiting or tending God's houses of worship". As regards their exclusion from the central mosque of Islam at Mecca ("the Inviolable House of Worship"), see verse 28 of this surah.