Franz Xavier Winterhalter (1805-1873) Young Italian Girl by the Well
'So Moses and Aaron said to all the people of Israel, "At evening you shall know that it was the LORD who brought you out of the land of Egypt, and in the morning you shall see the glory of the LORD, because he has heard your grumbling against the LORD. For what are we, that you grumble against us?" And Moses said, "When the LORD gives you in the evening meat to eat and in the morning bread to the full, because the LORD has heard your grumbling that you grumble against him— what are we? Your grumbling is not against us but against the LORD." '
-Exodus 16:6-8 (ESV)
When we complain about or against a person or thing we are really complaining against God. We are saying that He is not capable of caring for us and of meeting our needs. God, in His patience and mercy, must prove Himself and His power to us over and over again. He must lead us through trials and tests in order to bring us back and make us lean on Him again.