On the way to the place of sacrifice, what did Abraham place on Isaac to carry?

Answer: The wood for the offering

Abraham laid the wood for the burnt offering on Isaac, while he himself carried the fire and the sacrificial knife.

“Abraham took the wood for the burnt offering and placed it on his son Isaac. He himself carried the fire and the sacrificial knife, and the two of them walked on together.”— Genesis 22:6 (BSB)