How do we know Christ's death was substitutionary?

The concept of substitutionary atonement is foundational in the understanding of Christ’s sacrifice. Isaiah 63:3 illustrates Christ treading the winepress alone, which signifies Him bearing the judgment meant for His people. The blood on Christ's garments, while depicted as others' blood, ultimately represents His own blood shed for the redemption of sinners. This substitution conveys that while the penalty for sin is death, Christ, who is without sin, took that penalty upon Himself. The New Testament further confirms this, portraying Jesus as our surety who fulfilled the demands of the law on our behalf.