NEIGHBOURS.
Arabic jar جار, pl. jiran. The Sunnis hold that neighbours are those who worship in the same mosque, but Shi’ah doctors say that a neighbour is anyone whose house is within forty cubits. while others maintain that the term extends to all the occupants of forty houses on either side. (Baillie’s Digest, Sunni Code, p. 579 Im. Code p. 216.)
A neighbour has the next right of preemption to a partner in the sale and purchase of houses and lands. (Hidayah, vol. iii. p. 562)
The rights of a neighbour in ease of the sale of property, are established by the Muslim law, for the Prophet has said that the neighbour of a house has a superior right, to the purchase of that house (i.e. next to immediate relatives), and the neighbour of lands has a prior claim to the purchase of those lands, and if he be absent, the seller must wait his return. (Hidayah, vol. iv. p. 562.)
Muslims are enjoined in the Qur’an (Surah iv, 40) to be kind to their neighbours. In the Traditions, it is said that Muhammad was so frequently advised by the angel Gabriel to order his people to be kind to their neighbours, that he almost imagined that he’ (the angel) wished to make neighbours heirs to each other. It is also related that the Prophet said, “Hie is not a perfect Muslim who eats to his full and leaves his neighbour hungry.”
Abu Hurairah says that a man once said to the Prophet. “There is a woman who worships God a great deal. but she is very abusive to her neighbours.” And the Prophet sal ” She will be in the fire.” The man then said, “But there is another woman who worships little and gives but little in alms, but she does not annoy her neighbours with her tongue?” The Prophet said, “She will be in Paradise.” (Mishkat, book xxii. ch. xv.)

Based on Hughes, Dictionary of Islam