‘Does the fountain send forth from the same opening sweet water and bitter?'
The writer now illustrates the matter in different ways. The ‘coming forth' from the mouth and the ‘blessing and cursing' now leads on to the ‘sending forth' from a fountain or spring, and the idea of ‘sweet, thirst-quenching water and bitter water'. Can a fountain or spring from the same opening (or crevice in the rock) produce both sweet water and bitter? Nature is not so inconsistent. Only man behaves in such a foolish way.
Not having water on tap all James' hearers knew how important it was whether a spring was drinkable or not. The spring could be a thing of blessing or a thing of cursing, a thing of great joy and refreshment, or a huge disappointment. But it could never be both. So those from whom should come springs of living water (John 7:38) must not also be the means of poisoning the minds and hearts of their brothers and sisters.