take back his wife whom he has divorced if his intention is to harm her, for Allah Most High says:

“Do not retain them to harm them and thereby transgress.” [al-Baqarah: 231]

But if he has a legitimate purpose—for example, he wishes to make use of his property by converting it into apartments and renting them out—then he may do so.

If their shared wall collapses, or it is feared that it may cause harm, and one of them asks the other to rebuild it with him, the other may be compelled to do so. The same applies to a river, waterwheel, and canal.

His statement, “If their shared wall collapses, or it is feared that it may cause harm, and one of them asks the other to rebuild it with him, the other may be compelled to do so,” means that in the phrase “their wall,” the pronoun refers to the two neighbours. That is, this is a wall jointly owned between their two properties and originally built at their shared expense. If the wall collapses and one of them asks the other to rebuild it, but the latter says, “I will not rebuild it, because I have no need for the wall,” then he may be compelled to do so, because he is his neighbour’s partner and may be required to maintain that which they jointly own.

If one of them wishes to demolish it and rebuild it with concrete, whereas it had been built of mud bricks, may the other be compelled?

The answer is no, because there is a difference between repairing what has deteriorated and embellishing, ornamenting, or replacing it with something better. The other partner may be compelled to repair what has deteriorated—for example, if the wall has collapsed, or if it is feared to cause harm because it has begun to lean or crack. But he cannot be compelled to replace it with something better.

If one of them says, “I wish to undertake this work at my own expense,” while the wall is jointly owned, and the other partner refuses, then the matter should be examined. If his refusal is motivated by spite toward his neighbour, and the experts say that, if the wall is constructed in the