On what basis does Peter hold the nation of Israel responsible for rejecting Jesus?
Therefore, Peter's basis is covenant ground: Israel should have known better. They rejected and crucified the Messiah whom God sent to fulfill the Abrahamic covenant, and God raised Him and made Him both Lord and Christ, as Scripture had foretold.
Les teaches that Peter, after laying out how they had crucified their Messiah and how the Psalms foretold He must suffer, die, and be raised, says all the house of Israel should know assuredly that God made that same Jesus, whom they crucified, Lord and Christ. Peter puts the blame on the nation of Israel, dealing with them on covenant ground: they, who should have known better, rejected the One God sent to fulfill the Abrahamic covenant and others. Though they precipitated it, Psalms 2:1 shows the kings of the earth and people consort together, so the whole human race is guilty. When they heard this, the Spirit convicted them and they were pricked in their heart.