Heaven is everlasting and earth is enduring.
The reason that they are everlasting is because they do not exist for themselves. Hence, they are long lived.
Thus, although the saint puts himself last, finds himself in the lead. Although he is not self-concerned, finds himself accomplished.
It is because he is not focused on self-interests and hence can fulfill his true nature.
Heaven and Earth will exist forever because they are the known presence of the unknown Tao. (God)
The wise man understands the meaning of “oneness” therefore as he quietly remains in shadow, his spirit dances in the sun light for all to see.