易經 · BOOK OF CHANGES No. 48
井
Jǐng — The Well
Water over Wind
The Well. The town may be changed, but the well cannot be changed. It neither decreases nor increases. They come and go and draw from the well.
Water over wood — the well draws from inexhaustible depths. Towns move; the well remains. Tend your own deep source. If the rope is too short or the jug breaks, the water is there but useless — maintain your means of access.