Come, buy without money

Every time I hear or read this passage, I respond in two ways: on the one hand I am joyful, and on the other convicted. Isaiah 55:1-3:

Come, everyone who thirsts, come to the waters;
and he who has no money,
come, buy and eat!
Come, buy wine and milk
without money and without price.
Why do you spend your money
for that which is not bread,
and your labor for that which does not satisfy?
Listen diligently to me, and eat what is good,
and delight yourselves in rich food.
Incline your ear, and come to me;
hear, that your soul may live;
and I will make with you an everlasting covenant,
my steadfast, sure love for David.

I respond with joy because God has chosen to richly satisfy us. We are parched, starving paupers, and God invites us to come and partake of the bounty that is himself the only thing in life that can truly satisfy. He offers endless delight and live. He offers us a portion of the everlasting covenant that He has made with David.I respond with sadness because I realize that I too often strive for satisfaction in the wrong places. I spend my resources on things that can never satisfy, when all the time I could be freely partaking of eternal satisfaction that costs me nothing.