(1) According to 1 Peter 2.24, “Jesus Himself bore our sins in His body on the tree (i.e. the cross), that we might die to sin and live to righteousness. By His wounds you have been healed.” Peter tells us here that on the cross Jesus provided atonement for the sins of sinners. He bore the guilt and punishment that sinners deserve to receive from God because of their sin against Him. However, because of this atonement on the cross, there is now no condemnation for those who are in Christ Jesus – those who are trusting in Him alone (Romans 8.1; see also Romans 6.23 and Colossians 2.13-14).
(2) When Jesus called out from the cross, “It is finished!” and then died (John 19.30), He was declaring that by His death the just demands of the Law were satisfied for those who believe in Him. Jesus came and lived a perfect life to fulfill the law and the prophets (Matthew 5.17) because not one of us could ever be justified by obedience to the works of the law (Galatians 2.16). Justification, the declaration by God that the believer in Jesus is righteous, comes by faith alone in Jesus alone. Faith in Jesus is enough because the finished work of Jesus on the cross was enough (see also Ephesians 2.8-9).
(3) According to Hebrews 10.14, by the single offering of Himself, Jesus has perfected for all time those who are being sanctified – those who are set apart for God. Through His death, Jesus obtained perfection for us. This perfection is imputed/given to those who trust in Jesus alone (see also 2 Corinthians 5.21).
Just these few reasons are why Christians consider Good Friday “good.” Of course Good Friday would never exist on our calendar if not for the following “Good” Sunday – the day Christians celebrate the fact that God raised Jesus from the dead (Acts 2.24). If the body of Jesus were still in the grave – if the body of Jesus had decayed just like all other dead bodies – if the body of Jesus had not been raised to new life, then there would be no hope for the Christian to experience the same resurrected new life. “But in fact Christ has been raised from the dead” (1 Corinthians 15.20), therefore the Christian does have what Peter calls a “living hope” (see 1 Peter 1.3).
Therefore, because of the death and resurrection of Jesus the promises of atonement, justification, perfection, and eternal life are secured even now for those whose hope is Jesus alone. Christians can rest assured that all their sins (past, present, and future) are forgiven not because of what they have done, but because of what Jesus has done. This is why Good Friday and the subsequent Resurrection Sunday are good.
Is this coming Good Friday a good day for you? It will be if your hope for full forgiveness of sins and salvation is built on nothing less than Jesus blood and righteousness. I pray that it will be.