No one is allowed to reserve any spot in the mosque
12-1-2014 | IslamWeb
Question:
Is it permissible to reserve a spot in the first row in the mosque when going away for more than an hour?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
Shaykh Al-Islam Ibn Taymiyyah 
was asked in Al-Fataawa (vol. 22, p. 193) about the one who reserves a spot in the mosque with a mat, rug or the like and if it is prohibited. If someone prays over something like that without the permission of its owner, is this disliked or not?
His answer was as follows: “No one has the right to reserve any spot in the mosque, not a mat before his presence, rug or anything as such. No one other than himself is permitted to pray over it without his permission. However, he can remove it and pray in its place according to the more preponderant of the two opinions of the scholars.” End quote
He said in another situation: “If someone occupies a spot in the mosque for praying, reciting, remembering Allaah The Almighty, learning knowledge, observing I‘tikaaf or the like, then he has more right to it until he finishes this task. No one has the right to dismiss him from it. This is because the Prophet, sallallaahu ‘alayhi wa sallam, prohibited dismissing someone from his place. However, he should make room for others and, if his ablution is nullified and he comes back, then he has more right to this place for the Prophet, sallallaahu ‘alayhi wa sallam, said: “If someone gets up from his place then comes back to it, he has more right to it.”
Ibn Taymiyyah also said in another situation: “No one has the right to put something in a spot of the mosque to reserve it for himself and prevent others to reach it while he is absent. This is a kind of usurpation and preventing Muslims from what Allaah The Almighty Commanded regarding prayer. Also, the Sunnah entails that one should precede to the first row by being present. However, the one who reserves his place in the first row with a mat is unjust if he does not stop doing this. Those mats should be removed and people should be enabled to pray in their places. Also, using mats to reserve spots in the mosque is originally an innovation, especially in the mosque of the Prophet, sallallaahu ‘alayhi wa sallam. When ‘Abdur Rahmaan ibn Mahdi came from Iraq and placed a mat in the mosque, Maalik ibn Anas, may Allaah Have mercy upon him, commanded putting him in jail as a kind of discretionary punishment until he was asked to reconsider the matter. Then he mentioned that doing this in this mosque is an innovation and that the one who does it should be disciplined.”
Accordingly, people should blame and prevent the one who does this, especially those who are responsible for the mosque. They have to remove these mats. Actually, if the one who does this is punished by giving out such mats in charity then this will be an acceptable kind of Ijtihaad (i.e. juristic reasoning)."
What Shaykh Al-Islam Ibn Taymiyyah has said is the sound and preponderant opinion.