"My people have committed two sins: They have forsaken me, the spring of living water, and have dug their own cisterns, broken cisterns that cannot hold water" (Jeremiah 2:13).
Do you see the difference between these two sins? The first is forsaking an artesian well, a flowing spring of life-giving water. There is no end to the supply. God is this life-giving spring. To forsake Him is both evil and foolish.
The second sin has to do with recognizing the need for water, but trying to get it from a cistern. The sin is digging the cistern. It is salvation by effort. Digging a cistern does not provide water to fill it. Even if water came, it would be stagnant. There is another problem, too: it is a leaky cistern. Soon there will be no water, not even stagnant water. Digging this cistern is a foolish attempt at creating your own salvation. It does not provide life.
"Jesus answered, 'Everyone who drinks this water will be thirsty again, but whoever drinks the water I give him will never thirst. Indeed, the water I give him will become in him a spring of water welling up to eternal life'” (John 4:13-14).