Therefore when Jesus had received the sour wine, He said, "It is finished!" And He bowed His head and gave up His spirit. John 19:30 (NASB)

What exactly did Jesus mean by these last words upon the cross? How we interpret them will somewhat depend on our view of Scripture and life. For the pessimist, maybe they were the last words of a defeated man who died tragically for nothing. For the more positive minded, perhaps Jesus was simply relieved that he had made it through the worst and finally would find escape in death. But what about the believer? What truth do we find in Jesus’ last words upon the cross? I believe he gave us the clue we need in a previous discourse.

Jesus spoke these things; and lifting up His eyes to heaven, He said, "Father, the hour has come; glorify Your Son, that the Son may glorify You, 2 even as You gave Him authority over all flesh, that to all whom You have given Him, He may give eternal life. 3 "This is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent. 4 "I glorified You on the earth, having accomplished the work which You have given Me to do. 5 "Now, Father, glorify Me together with Yourself, with the glory which I had with You before the world was. John 17:1-5 (NASB) 

Even before his crucifixion, Jesus could confidently say that He had accomplished the work his Abba Father had given Him to do. How much more could he claim that upon the cross as his last breath was exhaled as an act of total obedience to His Father’s will.

For us to understand what is meant by the finished work of Christ, we must go back to the “once for all” aspect of salvation.

The Bible makes it clear that Jesus died once and will never need to do that again, having purchased our salvation through His ultimate sacrifice.

He does not need to offer sacrifices every day like the other high priests. They did this for their own sins first and then for the sins of the people. But Jesus did this once for all when he sacrificed himself on the cross. Hebrews 7:27 (NLT) 

As we consider the nature of what Jesus did on the cross, we must engage our minds to think quite deeply. This was not a simple or superficial thing. C.S. Lewis, in his Chronicles of Narnia, which is an allegory about Christ, calls it “deep magic”. Of course, there was nothing magical about it, but it was “deep”. Paul calls it God’s “secret wisdom”.

Yet when I am among mature Christians, I do speak with words of wisdom, but not the kind of wisdom that belongs to this world, and not the kind that appeals to the rulers of this world, who are being brought to nothing. 7 No, the wisdom we speak of is the secret wisdom of God, which was hidden in former times, though he made it for our benefit before the world began. 8 But the rulers of this world have not understood it; if they had, they would never have crucified our glorious Lord. 9 That is what the Scriptures mean when they say, "No eye has seen, no ear has heard, and no mind has imagined what God has prepared for those who love him." 10 But we know these things because God has revealed them to us by his Spirit, and his Spirit searches out everything and shows us even God's deep secrets. 1 Corinthians 2:6-10 (NLT)

In the Bible a “mystery” is something hidden until it is revealed by God.

What Christ accomplished on the cross and through His resurrection is just such a mystery.

God's secret plan has now been revealed to us; it is a plan centered on Christ, designed long ago according to his good pleasure. 10 And this is his plan: At the right time he will bring everything together under the authority of Christ—everything in heaven and on earth. 11 Furthermore, because of Christ, we have received an inheritance from God, for he chose us from the beginning, and all things happen just as he decided long ago. 12 God's purpose was that we who were the first to trust in Christ should praise our glorious God. 13 And now you also have heard the truth, the Good News that God saves you. And when you believed in Christ, he identified you as his own by giving you the Holy Spirit, whom he promised long ago. 14 The Spirit is God's guarantee that he will give us everything he promised and that he has purchased us to be his own people. This is just one more reason for us to praise our glorious God. Ephesians 1:9-14 (NLT)

The mystery is that God’s salvation was accomplished in and through Christ via the cross and resurrection.

God’s eternal plan to conform us to His glorious image has been carried out to perfection through His Son’s ultimate sacrifice and his indwelling life (“Christ in you, the hope of glory” – Col.1:27). This plan was conceived in the mind of Abba Father before the world was created. (Ephesians 1:4)

The Holy Spirit applied Christ’s finished work to our lives when the gospel intersected our timeline.

Here is another passage that clarifies the plan.

For those whom He foreknew, He also predestined to become conformed to the image of His Son, so that He would be the firstborn among many brethren; 30  and these whom He predestined, He also called; and these whom He called, He also justified; and these whom He justified, He also glorified. Romans 8:29-30 (NASB) 

Every key verb in the above passage is in the Greek aorist past tense, which means it is a once for all completed action, a “done deal”.

Our faith is not in something shifting or uncertain.

We have been given a strong anchor that is hooked into Christ’s finished work.

So God has given us both his promise and his oath. These two things are unchangeable because it is impossible for God to lie. Therefore, we who have fled to him for refuge can take new courage, for we can hold on to his promise with confidence. 19 This confidence is like a strong and trustworthy anchor for our souls. It leads us through the curtain of heaven into God's inner sanctuary. 20 Jesus has already gone in there for us. He has become our eternal High Priest in the line of Melchizedek. Hebrews 6:18-20 (NLT) 

As we continue to trust in what God has already done for us in Christ, we have the stability to navigate through the uncertainties of our “fragile” earthly existence in these mortal bodies.

Despite having to do battle with renegade desires coming from the “flesh,” we have bold confidence that ultimately our salvation is complete and does not depend on our performance but on Christ’s perfect work.

God sees the end from the beginning. The Holy Spirit Who indwells us is God’s guarantee that what He has begun, He will finish. In fact, it is finished!

For I am confident of this very thing, that He who began a good work in you will perfect it until the day of Christ Jesus. Philippians 1:6 (NASB) 

God himself has prepared us for this, and as a guarantee he has given us his Holy Spirit. 2 Corinthians 5:5 (NLT) 

Questions for Further Study and Discussion

• What difference does it make for us to know that Christ already completed the work of salvation?
• How does our understanding of “spirit-soul-body” help us to grasp the difference between the “once-for-all” eternal salvation of the spirit and the “in process” daily salvation of the soul?
• What part does each Person of the Godhead play in our salvation?
• Does Christ’s death on the cross also cover all of our present and future sins or just those in our past?
• If Jesus already paid for our forgiveness, what place does repentance have in the process?