Cutting the wood to sacrifice Isaac was the last thing that Abraham did when he set out for Moriah. He had prepared the servants, he had saddled the donkey and then went to cut the firewood! See the sequence of events: 'So Abraham rose early in the morning, saddled his donkey, and took two of his young men with him, and his son Isaac. And he cut the wood for the burnt offering and arose and went to the place of which God had told him' (Gen 22:3, ESV). He should have cut the wood the previous evening, before going to bed. Preparing the servants, and saddling the donkey could be in the morning. Taking time to cut the wood in the morning would certainly delay the journey. We can't explain Abraham's peculiar behavior; only some guesses. Maybe he was expecting God to intervene before they set out. Did Abraham think that getting up in the morning, saddling the donkey and getting the servants ready will send enough clues to God that he is willing to obey and expect him to
“I don't know what I think until I write it down.” ― Joan Didion.