nor reciprocating harm.” (1) However, if it does not harm the wall, then he may not prevent him, so long as he needs to do so.
If the neighbour says, “Set up two posts, place a crossbeam between them, and rest the timber on them from inside your house,” he is not obliged to do so. For if we were to say that he is obliged, the hadith mentioned by the Prophet ﷺ would have no meaning whatsoever: “Let no neighbour prevent his neighbour from driving his timber into his wall.” The prohibition here indicates that it is forbidden. The Prophet ﷺ prohibited such prevention because placing the timber benefits both the owner of the wall and the neighbour.
The benefit to the neighbour is clear: he is spared from having to erect posts and strong roofing capable of supporting the timber. As for its benefit to the owner of the wall, the timber braces and strengthens the wall and protects it from the sun and rain. Thus, there is benefit for both parties. This is why the Prophet ﷺ prohibited a neighbour from preventing his neighbour from placing his timber upon his wall.
Abu Hurayrah said, “Why do I see you turning away from it? By Allah, I shall surely cast it between your shoulders.” (2) He said this when he was governor of Madinah. His words may bear two meanings:
The first meaning is: “Why do I see you turning away from it”—that is, from this sunnah—“By Allah, I shall surely cast it between your shoulders.” He specifically mentioned the shoulders because they are the place where burdens are borne.