“I once asked abu ‘Abd Allah (a.s.), about a man who on a journey has a knife in his slipper without which he cannot do anything or it is in his pant, and a key which he is afraid of losing it, or that around his midsection is a belt in which there is iron. He (the Imam) said, ‘It is not an offense to have a knife, or a belt for a traveler in case he needs them as well as a key for which one is afraid about forgetting it. It is not an offense to have a sword or weapons during a war and in other times. It is not permissible to perform Salah (prayer) with iron; it is Najis (unclean) and metamorphosed. ’ ”