The scriptures were written for an audience who knew what spirits are. They knew about three kinds of spirits. More ancient scriptures show this. They knew about 1) ghosts = spirits of humans, 2) gods = spirits of non-human and non-animal beings (like ghosts which have never had a human existence or animal existence), and 3) partial human, partial god spirits. Cuneiform symbols capture this knowledge. There is a symbol for ghost, a symbol for deity, and a symbol combining the two. Scientific materialists have forbidden this belief in the last century or so. Obviously not everyone believes scientific materialists. A subset of non-human spirits is elemental spirits. Elements of nature have spirits. This is behind a lot of pagan ritual but also forms part of godly life, as seen is weird passages of scripture and mysterious doctrines such as some of the more mysterious things sometimes commanded by God. A concept or quality can have an essence which has a spirit.
