“This stone will be a witness”
You see this stone. It will be a witness against us, for it has heard all the words the LORD has spoken to us, and it will be a witness against you if you ever deny your God. (Joshua 24:27 BSB)
What it sounds like today
A poetic flourish about a rock that supposedly listens.
The cultural key
Ancient treaties were not valid without witnesses, and lacking the pagan gods that neighboring treaties invoked, Israel's covenants summon other witnesses: heaven and earth (Deuteronomy 30:19), a song, or, here, a standing stone. Joshua sets up a large stone at Shechem's sanctuary and personifies it as having 'heard' the covenant words, so that it can testify against the people if they break faith. Standing stones (matzevot) commonly marked covenants and sacred encounters in this world; here one becomes the silent, permanent witness to Israel's oath.
Recovered meaning
The stone is the covenant's witness, standing guard so the people cannot later claim they never swore. In a culture where treaties needed witnesses, Israel calls creation itself, heaven, earth, even a rock, to hold it to its word.