Then they came to the place of which God had told him; and Abraham built the altar there and arranged the wood, and bound his son Isaac and laid him on the altar, on top of the wood.
Genesis 22:9 (NASB)
The rabbis point out that the word for “altar” here is in the definitive form. It is not an altar (as some translations render it), but it is the altar. The word “built” also means “re-built,” using the same stones.
According to rabbinical tradition, this is a specific and special altar, upon which Adam, Abel, and Noah have all sacrificed. And it points forward to the Temple.