Joshua 22:27 explains the altar's purpose as a witness — here they name it Ed to memorialize that witness.

Joshua 24:27 uses a stone as a witness — similar concept of a tangible covenant reminder, but different object.

1 Kings 18:39 echoes the declaration 'the LORD is God' — the same confession made here about the altar.

Isaiah 19:20 describes a sign and witness for the LORD — similar to this altar as a physical witness.