d's heat does not enter heaven at all,
because it is too gross, and is natural, and not spiritual; but with
men it is otherwise, because they are in both the spiritual world and
the natural world. As to their spirits they grow warm in exact
accordance with their loves; but as to the body they grow warm both
from the heat of their spirit and from the heat of the world. The
former flows into the latter, because they correspond. The nature of
the correspondence of the two kinds of heat can be seen from animal
life, in that the love of animals-the chief of which is the love of
propagating offspring of their kind-bursts forth and becomes active
in accordance with the presence and influence of heat from the sun of
the world, which is the heat of the spring and the summer seasons.
Those who believe that the world's heat flows in and excites these
loves are greatly mistaken, for there can be no influx from the
natural into the spiritual, but only from the spiritual into the
natural. This influx is of Divine order, but the other would be
contrary to Divine order.{1}

{Footnote 1} There is spiritual influx, but not physical, that
is, there is influx from the spiritual world into the natural,
but not from the natural world into the spiritual (n. 3219,
5119, 5259, 5427, 5428, 5477, 6322, 9109, 9110, 9111).

136. Angels, like men, have understanding and will. The light of
heaven constitutes the life of their understanding, because that
light is Divine truth and Divine wisdom therefrom; and the heat of
heaven constitutes the life of their will, because that heat is
Divine good and Divine love therefrom. The veriest life of the angels
is from heat, and from light only so far as heat is in it. That life
is from heat is shown by the fact that when heat is taken away life
perishes. The same is true of faith without love or of truth without
good; since the truth that is called truth of faith is light, and the
good that is called good of love is heat. {1} This is more clearly
shown by the heat and light of the world, to which the heat and light
of heaven correspond. By the world's heat when conjoined with light,
as in spring and summer, all things on the earth are quickened and
grow, but by light separate from heat nothing is quickened or grows,
but everything lies torpid and dies. They are not conjoined in
winter, when heat is absent though light remains. From this
correspondence heaven is called paradise, since truth is there