Ogun is iron, and by extension every tool, weapon, vehicle and machine made of it, so his devotees include blacksmiths, hunters, soldiers, surgeons, mechanics and drivers. The oath sworn on iron — touching or licking a blade or a piece of metal — carries a weight in Yoruba society that has attracted the attention of Nigerian legal practice, where the swearing of traditional oaths has been used in courts and by police because of a widely observed pattern: individuals who will swear falsely on a Bible or a Quran will decline to swear on Ogun. The practice has been formally debated in Nigerian legal circles and used in specific cases, including in disputes and in anti-corruption contexts. Practitioners draw the obvious conclusion about which system of belief is actually operative for the swearer. Ogun's praise names emphasise his violence and his indispensability together — he clears the road and he kills — and he is not a comfortable figure.