Exodus 8:27
We will go three days’ journey into the wilderness, and sacrifice to the Lord our God, as he shall command us.
Cross-reference
Exodus 3:18
Citation
Exodus 3:18 is the original command for the three-day journey — now Moses repeats it.
Exodus 5:1
Parallel
Exodus 5:1 records the initial request to Pharaoh for a feast in the wilderness — same as this.
Exodus 10:26
Parallel
Exodus 10:26 reaffirms the necessity of taking livestock for sacrifice — the same worship requirement.