Expositor's Bible Commentary Commentary Acts 2:37

"Now when they heard [this,] they were pricked in their heart, and said unto Peter and the rest of the apostles, Brethren, what shall we do?" — Acts 2:37 (ASV)

Peter’s preaching had been effective. The people were “cut to the heart” at the awful realization that in crucifying their long-awaited Messiah they had rejected their only hope of salvation. So with deep anguish they cried out, “Brothers, what shall we do?”

The phrase “cut to the heart” may have been drawn from Ps 109:16, the same psalm Luke had earlier applied to Judas . There it is a vivid phrase for those who stand with God’s servant in opposing the wicked men: “those who have been cut to the heart” or those who are “the humble of heart” because they realize their need and are open to God’s working.