A.T. Robertson Commentary Galatians 3:13

"Christ redeemed us from the curse of the law, having become a curse for us; for it is written, Cursed is every one that hangeth on a tree:" — Galatians 3:13 (ASV)

Redeemed us (ημας εξηγορασεν). First aorist active of the compound verb εξαγοραζω (Polybius, Plutarch, Diodorus), to buy from, to buy back, to ransom. The simple verb αγοραζω (1 Corinthians 6:20; 1 Corinthians 7:23) is used in an inscription for the purchase of slaves in a will (Deissmann, Light from the Ancient East, p. 324). See also Ga 4:5; Colossians 4:5; Ephesians 5:16. Christ purchased us

from the curse of the law (εκ της καταρας του νομου). "Out from (εκ repeated) under (υπο in verse 10) the curse of the law."

Having become a curse for us (γενομενος υπερ ημων καταρα). Here the graphic picture is completed. We were under (υπο) a curse, Christ became a curse

over (υπερ) us and so between us and the overhanging curse which fell on him instead of on us. Thus he bought us out (εκ) and we are free from the curse which he took on himself. This use of υπερ for substitution is common in the papyri and in ancient Greek as in the N.T. (John 11:50; 2 Corinthians 5:14f.).

That hangeth on a tree (ο κρεμαμενος επ ξυλου). Quotation from De 21:23 with the omission of υπο θεου (by God). Since Christ was not cursed by God. The allusion was to exposure of dead bodies on stakes or crosses (Joshua 10:26). Ξυλον means wood, not usually tree, though so in Lu 23:31 and in later Greek. It was used of gallows, crosses, etc. See Ac 5:30; 10:39; 1 Peter 2:24. On the present middle participle from the old verb κρεμαννυμ, to hang, see on Mt 18:6; Acts 5:30.