Why was the field called the Field of Blood: for the blood money, or for Judas’s death?

The two reasons are not rivals, and Acts itself gives both. Luke writes that Judas “purchased a field with the reward of iniquity”, died there, and that “it was known unto all the dwellers at Jerusalem” (Acts 1:18–19). What was known was the whole story: the price of the betrayal and the death that followed. That is why the field was called in Aramaic Aceldama (ḥaqel dema, ‘field of blood’). Luke’s ‘reward of iniquity’ is Matthew’s ‘price of blood’: the thirty pieces of silver paid for “innocent blood”, as Judas himself put it (Matthew 27:4).

Each writer stresses the side that serves his account. Matthew is telling of the priests’ scruple over the money and of the prophecy it fulfilled, so he links the name to the purchase. Luke is explaining to readers outside Jerusalem why the name was on everyone’s lips, so he links it to Judas’s end. A place can easily gather a name for more than one reason, and a field bought with a traitor’s blood money, where the traitor himself met a bloody death, would be called the Field of Blood on both counts. Gill reads the passages this way. For how the two accounts of Judas’s death fit together, see ‘How did Judas die?’.

Two fields

Ellicott mentions that since Jerome’s time two places near Jerusalem have been shown as the Field of Blood, and that two fields may have borne the name for different reasons. This is possible, but it is not needed, since Acts itself ties the field to Judas’s money.