  Few recent generations of cosmologists have solved non-local newtonian
equations of the gravitational instability in an expanding universe. In this
approach pancaking is the predominant form of first collapsing objects.
Relativistic counterparts of these equations contain the electric and magnetic
parts of the Weyl tensor. In the linear theory the magnetic part is associated
with gravitational waves. If the magnetic part is ignored, then the newtonian
limit of the relativistic equations is reduced to the closed set of the local
Lagrangian equations. Recently this fact drew much attention since the
gravitational instability in that form would greatly simplify the study of
cosmic structure formation. In particular, the filamentary structure of
collapsing is predicted. In this paper we resolve the contradiction between the
newtonian theory and relativistic version adopted in some recent papers. We
show that dropping the magnetic part from the basic relativistic equations is
{\it incorrect}. The correct newtonian limit is derived by the $1/c$-expansion
of the GR equations and the Bianchi identities for the Weyl tensor. The last
ones begin with $\sim 1/c^3$ order, therefore one {\it must} take into account
the magnetic part in the post newtonian order $\sim 1/c^3$, which contains
non-local terms, related to the non-local gravitational interaction. For the
first time we rigorously show that the GR equations with the magnetic part are
reduced precisely to the canonic newtonian non-local equations. Thus, the
correct treatment of the relativistic version of the gravitational instability
resurrects the canonic picture of the structure formation.
