Expositor's Bible Commentary Commentary Hebrews 8:4

"Now if he were on earth, he would not be a priest at all, seeing there are those who offer the gifts according to the law;" — Hebrews 8:4 (ASV)

We must be clear that Christ’s priesthood is not one of this earth (even though his offering of himself took place here). There are divinely appointed earthly priests, but Jesus has no place among them. On earth he was a layman, who performed no priestly functions in any earthly sanctuary. Those functions were performed by the priests to whom God had entrusted them. Christ’s priestly functions must obviously, then, be exercised elsewhere, in the true sanctuary in heaven.