How do we know Christ could not have sinned?

Christ's inability to sin is grounded in both His divine nature and the prophecies fulfilled in Him. The Bible declares Him to be 'without sin' (1 Peter 2:22) and 'without blemish' (Hebrews 9:14), fulfilling the Old Testament requirements for a sacrificial lamb, as outlined in Exodus 12:5. Since Jesus was conceived by the Holy Spirit and not born of Adam's sinful lineage, He did not share our fallen nature but rather bore the holiness of God. Therefore, it was impossible for Him to sin, affirming the integrity of God's redemptive plan and ensuring the efficacy of the work He accomplished on the cross.