Pursuit of sustenance from the wrong source is always the thing that drives sin.
It was famine that drove Elimelech and Naomi to seek food in Moab, a place God had called them out of. Their pursuit of sustenance in Moab ultimately led to Naomi and her daughter-in-laws returning empty to Judah. Seeking food in the wrong places had not filled them up. So they returned to Judah, having heard that "the Lord had visited his people and given them food". And so with His bread, God drew Naomi, and Ruth along with her, back to Himself.
When the children of Israel were called out of Egypt, there came again then a time when, at least some of the people, longed to return. Why? Because "we remember the fish we ate in Egypt that cost nothing, the cucumbers, the melons, the leeks, the onions, and the garlic. But now our strength is dried up, and there is nothing at all but this manna to look at." (Numbers 11:5) Desiring the "bread" of Egypt, they were unable to partake with gratefulness of the bread provided for them by God, the manna. His bread, His provision, was really what their souls craved... but their human desires crowded their ability to see what they actually needed.
Satan came to Jesus, commanding him to prove himself by turning stones to bread. Jesus refused; even in his hunger, he realized that just a loaf of bread would not fill him up. The life and vitality he needed could come only from His Father. What he truly needed, he could only get from the Source of Life.
Seeking to have our longings, cravings, and desires fulfilled by people, circumstances, or our own strength will always leave us hungry still. "Man shall not live by bread alone, but by every word that comes from the mouth of God", Jesus told Satan. (Matthew 4:3-4) A crowd followed Jesus to Capernaum once, and they asked him, "What sign do you do, that we may see and believe you? What work do you perform? Our fathers ate the manna in the wilderness, as it is written, He gave them bread from heaven to eat." Jesus responded to them, "Truly, truly I say to you, it was not Moses who gave you the bread from heaven, but my Father gives you the true bread from heaven. For the bread of God is he who comes down from heaven and gives life to the world." They asked him to "give us this bread always", but when Jesus answered them saying, "I am the bread of life; whoever comes to me shall not hunger, and whoever believes in me shall never thirst" and they really struggled to grasp and live and believe that. (John 6)
We do too, sometimes. Forgetting the provision of God for us, we continue to struggle and strive for things that we actually already possess through our relationship with Him. Anything that God gives to us, He gives in order to draw us to Himself. Often, that provision comes in unexpected forms, and so we struggle with that. Other times, it comes in very astounding ways that we can see plainly and clearly, and our trust nearly explodes. But then we have to remember.
If we fail to remember the faithfulness of God, we find ourselves again in the Wilderness. "Ah, stubborn children, declares the Lord, who carry out a plan, but not mine, and who make an alliance, but not of my Spirit, that they may add sin to sin; who set out to go down to Egypt, without asking for my direction, to take refuge in the protection of Pharaoh and to seek shelter in the shadow of Egypt!" By contrast, He calls us to return to Him, and to trust again, placing our refuge in Him, and not pursuing sustenance of our own strength: "In returning and rest you shall be saved; in quietness and in trust shall be your strength."
"The Lord waits to be gracious to you, and therefore he exalts himself to show mercy to you. For the Lord is a God of justice; blessed are all who wait for him. For a people shall dwell in Zion, in Jerusalem; you shall weep no more. He will surely be gracious to you at the sound of your cry. As soon as he hears it, he answers you. And though the Lord give you the bread of adversity and the water of affliction, yet your Teacher will not hide himself anymore, but your eyes shall see your Teacher. And your ears shall hear a word behind you, saying, "This is the way, walk in it," when you turn to the right or when you turn to the left. Then you will defile your carved idols overlaid with silver and your gold-plated metal images. You will scatter them as unclean things. You will say to them, "Be gone!" And he will give rain for the seed with which you sow the ground, and bread..." (Isaiah 30)
All bread - the bread of adversity, the bread of prosperity - is given by the Teacher, to teach us of Himself. It is when we reject the idols, the pursuit of sustenance in the wrong places, that we can see the abundance provided in and by the Living Bread.