Our purpose in this article is to study the geometric properties of complete spacelike hypersurfaces immersed in the anti-de Sitter space \(\mathbb {H}_1^{n+1}\) . In this context, we introduce the notion of a linearized curvature function \(\mathcal {F}_{r,s}\) associated to such a spacelike hypersurface and, by applying some maximum principles to a second order differential operator \(\mathcal {L}_{r,s}\) naturally related to \(\mathcal {F}_{r,s}\) , we obtain new characterizations of totally umbilical hypersurfaces of \(\mathbb {H}_1^{n+1}\) which are isometric to certain hyperbolic spaces. Our approach also allows us to obtain some nonexistence results concerning complete noncompact spacelike hypersurfaces of \(\mathbb {H}_1^{n+1}\) .