But even though God revealed once more his power over their enemies, the Israelites soon forgot these signs and continued to complain and grumble, to long for their past way of life, to test the Lord, to be disobedient, to give in to fear. Basically, their hearts were hardened.
 
This basic mind set was captured in Psalm 95 as the psalmist centuries later addressed the people of his day, speaking in the name of God. He could as well be speaking to us in our desert experience: "Harden not your hearts as at Meribah, as in the day of Massah in the desert, where your fathers tempted me; they tested me though they had seen my works. Forty years I loathed that generation, and I said: They are a people of erring heart, and they know not my ways. Therefore I swore in my anger: They shall not enter into my rest"(Ps 95: 8-11).

What is the purpose of the spiritual desert? To get in touch with sin within us. Sin is what hardens our heart against God. Not just any sin, but the root or dominant sin of our life, the habitual sin which controls our life, the sin which is our god, the skeletin-sin in the closet of our heart which we are afraid to confront, the security blanket sin which we have clung to.for years, the sin we fall back into when we no longer can trust that God can provide for our needs, the convenient sin which is ready to satisfy us, even for a fleeting moment.