Israel is back in the land God promised their ancestors, but something is deeply wrong. They confess they are 'slaves' in a place meant for freedom.
This verse hits hard because it highlights a stark contrast. God gave the land to their fathers to 'enjoy its fruit and its good gifts' – a picture of abundance and freedom under God's rule. But now, they confess, 'we are slaves.' This wasn't a physical enslavement by a foreign power like in Egypt, but a political and economic subjugation. They were under the dominion of the Persian empire, paying tribute and subject to their rule.
This subjection is a direct consequence of their past disobedience. They chose not to be God's servants, and so they became servants to earthly kingdoms. It's a tragic irony: owning the land God gave them, yet not truly possessing it freely because of their sin.