The spells command shows you which spells are in your spellbook and also which ones are currently active. The spells are arranged into four sections the first being which of the offensive spells you have, the second curative and protective spells. The third section is miscellaneous, while the last is the currently active spells. If you want more help on spells in general type help spelllist or if you want help on a specific spell, type help <spellname>