Forever and ever: as long as heaven and earth exist. It takes a long time to describe. Also described as eternity (especially love).
Forever: as long as heaven and earth exist. It takes a long time to describe.
Endless: no beginning, no margin. Describe extremely long and wide.
The source is wide and long: source: source; Process: process. It has a long history. Metaphor has a long history.
Source depth and flow length: source: the source of the river; Process: process. The source is deep and flowing. Metaphor has a long history.
It has a long history: the source is far away and the water flow is very long. Metaphor has a long history.