What does Exodus 8:27 mean?
After rejecting Pharaoh's offering to sacrifice to the Lord in the land of Goshen (Exodus 8:25–26), Moses said Israel was obligated to go a full three days' journey into the wilderness. This was part of God's original command to Pharaoh (Exodus 3:18–20; 5:1–4). Pharaoh has resisted so far (Exodus 7:13, 23; 8:13–15, 18–19), knowing full well the Israelites won't be coming back (Exodus 1:11–14).Sacrifice, including animals, was part of worship of God since Adam and Eve left Eden (Genesis 4; 8:20; 31:54). Abraham sacrificed animals to the Lord (Genesis 15:8–10). In a famous incident, Abraham prepared to obey God's test regarding the sacrifice of his only son, Isaac, though God stopped him before it took place (Genesis 22). Jacob offered sacrifices before entering Egypt (Genesis 46:1).
It appears that animal sacrifices to the Lord had not been permitted during the entire time the Jews lived in Egypt. At the very least, none are recorded. The connection between leaving the land of Egypt and offering sacrifices to the Lord is strong. Physical and religious liberty are intertwined in the Jewish mindset. Their physical slavery also limited their ability to freely worship God (Exodus 5:7–9).