When I brought you into the garden land to eat its fruits, you entered and defiled my land and made my heritage loathsome. Prophet Jeremiah was “right” in his hesitance to accept his call to be a prophet (cf. Jeremiah 1:6), for in his first mission, he found himself sent to prophesy against Israel, God’s first born, and against Jerusalem, God’s sacred city. What was the sin of Israel about which he was to preach? Deserting the Lord.
God not only chose Israel but also nurtured her, leading her by the hand as she navigated her dangerous “teenage” years. However, when Israel came of age and was able to “stand on her own feet,” Israel turned her back on the Lord their God. Israel’s priests ceased to seek out the Lord, and her prophets forsook the Lord God for Baal (sin of idolatry). It was a turn of events that was both a slap in the face of God as well as an insult. What happened that made Israel to turn her back on her Lord and friend?
As Israel journeyed through the desert, Israel encountered many cultures and traditions, some of which Israel copied and even tried to assimilate. Israel had always been the “Lord’s.” Everything that was about her had always been attributed to the Lord. And this remained true as long as Israel was in need. However, when things “got better for Israel,” she forgot about the Lord God, becoming both unfaithful and ungrateful. It is this that angered the Lord: “ You have made my heritage loathsome,” says the Lord to Israel.  
The only thing that the Lord requires of God’s people is gratitude and fidelity, that is, the ability to walk with the Lord in and out of season. This is what Israel was quick to forget. Like most of us would do, Israel soon forgot about the Lord when her belly became full. Because she was not in need anymore, Israel began to act in a manner that could be interpreted to mean that she wanted to be independent.  She forgot that those who are known by the name of the Lord cannot have life apart from the Lord.