We calculate the cross section for the resonance scattering of Lyman-$\ensuremath{\alpha}$ radiation by spinless nonrelativistic hydrogen atoms in the ground state using a two-level model. A generalization of Dirac's resonance scattering theory is used together with the exact matrix elements for the electromagnetic interaction. In contrast to the usual treatments in which only the dipole approximation for the matrix elements are taken, the shift in position of the resonance is finite and has a value of 75% of the Lamb shift of the
n=1 state. Whether this latter fact is significant in renormalization calculations is left open.