How do we know the substitutionary sacrifice of Christ is true?

The Bible asserts the truth of Christ's substitutionary sacrifice as the only means through which salvation is obtained. This is encapsulated in Galatians 1:4, which states that Jesus gave Himself for our sins, clearly indicating that His sacrificial death serves as our substitute before God. Furthermore, Acts 4:12 declares there is no other name under heaven given among men by which we must be saved. The truth of Christ's sacrifice is foundational in Christian belief, showing that He fulfilled the requirements for atonement and secured our redemption through His blood.