He was also asked—may Allah Most High have mercy on him:
“Is it forbidden for someone to reserve a place in the mosque with a prayer mat, a carpet, or something else? If another person prays on any such item without its owner’s permission, is that disliked or not?”
He replied:
No one may reserve any part of the mosque, whether by laying down a prayer mat before arriving, a carpet, or anything else. Nor may another person pray on it without its owner’s permission. Rather, he should remove it and pray in its place, according to the more correct of the two scholarly opinions. Allah knows best.
He was asked:
“Is it permissible for a Christian or a Jew to enter the mosque, with or without a Muslim’s permission, or to use it as a thoroughfare?”
He replied:
A Muslim may not use the mosque as a thoroughfare, so how could a disbeliever do so? This must undoubtedly be prevented.