The brass nail with sacred Arabic inscriptions is a most unique item of Islamic magic. It features one of the most powerful magic spells in Arabic, namely 'Lafadz Allah' which invokes the blessings of Allah the Almighty. An Islamic magical item of this kind is often used for protection of one's house. It is common practice for Indonesian Muslims to bury one or more of these sacred nails in the ground near the entrance (door) to their house. This will help to ward off evil ghosts and spirits ('jinn') from approaching your house. It will also protect the household against black magic ('guna-guna').
Hence, by placing the sacred brass nail(s) into the earth where one's house is built, one thus creates a fence which serves as a powerful tool for protection against the dangers of the spirit realm. In ancient times people used brass nails with sacred inscriptions written in Arabic for fear of being attacked by certain types of kerises, which according to the legends, were capable of flying through the sky at night, and to kill a particular person on their own accord.
Though this is part of an ancient practice to evade all sorts of danger, yet the sacred nails are still being used by many Indonesians today. The primary reason for the popular demand for such nails with magical spells in Arabic on it can be explained by its multiple functions and wide variety in magical aspects. For instance, the mystical qualities of the powerful Islamic inscriptions can also be used for protection against one's enemies and to beat one's competitors.