Quark correlation functions and Bethe-Salpeter amplitudes for the pion, rho, and nucleon calculated in quenched lattice QCD are compared with the MIT bag model. The bag model is shown to reproduce the qualitative behavior of the density-density correlation functions for the rho and nucleon, the quark-mass dependence of observables, and ratios of pseudoscalar to scalar correlation functions. The origin and significance of substantial discrepancies in other observables are discussed.