How do we know that salvation is only through Christ's sacrifice?

Scripture reassures us that Christ’s sacrifice is wholly sufficient for the salvation of the elect. In Romans 3:23-24, we see how all have sinned but are justified freely by His grace. The resurrection of Christ serves as the ultimate proof of this truth; it demonstrated that every sin of the elect was paid in full. If there was any sin remaining unpaid, Christ would not have risen. This completion is essential in the gospel message, and any doctrine suggesting that human works can contribute to salvation undermines Christ’s finished work. Therefore, true faith rests solely on the merit of Christ's sacrifice.