If God didn't command sacrifices at first, how did they become such a central part of Israel's worship?
The text implies that sacrifices were not the purpose of the covenant, but rather a means to an end, introduced later or emphasized differently. When Jeremiah says God didn't command sacrifices 'in the day that I brought them out of the land of Egypt,' he's contrasting the foundational requirement of obedience with the subsequent ritualistic practices. While sacrifices were indeed part of God's instituted worship, they were valuable as signs and reminders—reminders of sin, the need for atonement, and a foreshadowing of Christ. However, when the people prioritized the act of sacrifice over the heart of obedience, these rituals became empty and detestable to God. They were 'added' or emphasized in response to the people's corruptions and tendency towards outward performance without inner devotion.