Paul's citation of Deut 21:23 in Gal 3:13 is often misunderstood, as Paul is frequently thought to be declaring that Jesus, by virtue of his crucifixion, fell under the curse which Deut 21:23 pronounces on victims of that form of execution. This, it is claimed, was the mechanism by which Jesus atoned for sin, as God transferred the curse resting on humans to Jesus, who bore it vicariously. There is no evidence, however, that Second Temple Jews read Deut 21 as cursing all crucifixion victims. Rather, a wealth of evidence suggests that they understood the Law to curse only those crucified victims who were truly guilty of capital offenses against God. Therefore, there is good reason to believe that Paul, himself a Second Temple Jew convinced of Jesus's innocence, did not believe that Jesus was cursed by God solely by virtue of his manner of death on a cross. Thus, Paul's language in Gal 3:13 when he speaks of Christ “becoming a curse” rather than becoming “accursed” is significant. It refers to Jesus's humiliation and execration at the hands of his fellow Jews, not his becoming vicariously cursed by God. It is thus not an explanation of the mechanism by which Christ achieved atonement. This reading receives virtually unanimous support from Patristic interpretations.
