During the war with Amalek, the Israelites were losing whenever Moses's hands grew heavy and fell. Aaron and Hur took a stone and placed it under him so he could sit and raise his arms (Exodus 17:12). A simple detail. But the rabbis lingered on it.
Why a stone, they asked. Could they not have found Moses a chair? A cushion? He was the leader of the people, the prophet of prophets. A rock was hard and cold.
Moses himself answered the question, they say. He chose the stone. He said: Since the children of Israel are in distress, sitting on hard ground and bleeding on the battlefield, I too will bear my part with them. I will not sit in comfort while they suffer. The one who bears his portion of the burden with the community will live to taste the hour of its consolation.
Then the passage issues a warning. Woe to the person who says, No one will notice. I will let my neighbors carry the weight, and nobody will know whether I did my part or not. Such a one is mistaken. The very stones of his house, the very beams of his walls, will rise up and testify against him, for it is written (Habakkuk 2:11): The stone shall cry out from the wall, and the beam from the timber shall answer it.
This teaching from the Mekhilta, preserved in Hebraic Literature (1901), imagines a courtroom where the plaintiffs are the walls of your own home. Every stone you have climbed, every beam that sheltered you, knew whether you shared the burden. And when the time comes, they will speak.