The Jews 'judged themselves unworthy of eternal life.' How can rejecting good news be a form of self-condemnation?
This is a powerful, cutting statement. When Paul and Barnabas say the Jews 'judge yourselves unworthy of eternal life,' it's not necessarily that the Jews thought 'we are unworthy.' Instead, their actions spoke volumes. By violently rejecting the 'word of God' – thrusting it away – they were, in effect, demonstrating that they did not value, and therefore were not worthy of, the eternal life that the Word offered.
It's like refusing a free, life-saving antidote because you don't believe you're sick. Your refusal itself proves you don't value the cure. Their stubborn opposition and slander against the apostles were a verdict they passed on themselves, an ultimate dismissal of God's gracious offer.