Describing the cross as a “tree” is rare and remarkable. Of course, the cross was made from wood. But describing it as a “tree” directs our attention to Deuteronomy 21:22–23, where the Lord commanded that the body of a person meriting capital punishment should (after death) be hung “on a tree…for a hanged man is cursed by God.” The picture would seem to be that this sinner should be lifted off God’s earth because his earth could no longer tolerate the presence of this offender. That Jesus was suspended “on the tree” expresses God’s curse on this “sinner” (note Peter’s explicit statement that “he himself bore our sins…on the tree”; see further Isaiah 53:4, Isaiah 53:12).
24 He himself bore our sins in his body on the tree, that we might die to sin and live to righteousness. By his wounds you have been healed.