Although friends don't see each other often, their friendship continues. How to describe it?

Green mountains do not change, and green waters often flow. Qingshan does not change its original intention, but it is perseverance. Green water often flows, which means eternal green hills and green water flowing forever. Green water often flows because of green mountains, and green mountains are green water. Unless the mountains and rivers change, they will not change, nor will hatred and friendship.