  We discuss a relation between the light-front quark model and QCD. We argue
that this model can be used for an evaluation of the light-cone wave functions
for moderate values of "u", but that it is inapplicable for this purpose in the
region near the ends points u=0,1. We find additional support for a recent
analysis in which it was claimed that the twist-two pion wave function attains
its asymptotic form. The asymptotic twist-four two-particle wave function is
also in good agreement with the light-front quark model.
