Once upon a time, there was an oasis in the middle of a desert. The desert was a dry wasteland where the sun burned hot. The heat rising from the blistering sand wearied many a traveler. But the oasis gave hope of refreshment to weary souls.
In the oasis was an artesian spring that gave the clearest, bubbling cool water that man has ever tasted. So much so, that its fame spread far and near. Travelers would come to the oasis just because they had heard of the refreshing spring. They drank deeply from its waters and found refreshment and contentment of soul.
Those who frequented the oasis decided to build a cistern near the spring. They used the finest materials and filled it with the pure water. They made the area around their cistern pleasant and comfortable, so that people began to prefer drinking from the cistern than the spring itself. At first no one noticed the difference.
But in time, the cistern became contaminated and leaked. The people began to drink smaller and smaller amounts. Having grown so fond of their cistern, they did not notice that they were weary and faint. They continued to go to the cistern acting as if they had forgotten the spring. Some grew weaker, and others perished in their journeys overcome by the desert’s heat.
for my people have committed two evils: they have forsaken me, the fountain of living waters, and hewed out cisterns for themselves, broken cisterns that can hold no water. (Jeremiah 2:13 ESV)