World without guns, firearms of any kind EVER ?

What do I need to make this possible ? No gunpowder check, no chemical propellants / explosives check, so what else do I need to make this work. I want a world eternally locked in stasis with both low tech and magic. Personal more physically engaging/strenuous one on one combat is what I am aiming for !

Edit : Magic does exist but is extremely limited for the same reasons I don't want guns. Limited magic application such as igniting fire, freezing water rich objects/people through touch...etc

Also on a side note how do I make a nation/cities (population in the millions maximum) with individual houses that have access to water, not running water or anything but enough to drink and shower and more importantly how to manage waste/sewage/poop ?

Thanks !