  We provide a novel approach to calculate the gravitational form factor of
pion under the ladder approximation of the Bethe-Salpeter equation, with
contact interactions. Central to this approach is a symmetry-preserving
treatment of the dressed $\pi\pi$ amplitude, which shows explicitly the
contributions from intrinsic quarks and bound states, the latter being
necessary to produce the $D$-term of pion in the soft-pion limit. The approach
we provide in this work can be applied to many processes of physical
significance.
