Jesus priority during His 3 & 1/2 years of ministry during the latter part of His life was centered on doing His Father's work.
Jesus said to them, "My food is to do the will of Him who sent Me and to accomplish His work (John 3:34).
The Lord's prayer as recorded in John 17, specifically in verse 4, that He had finished the work, which was in reference to His work during the ministry years in fulfilling His Father's will, or work during that time span.
So, I agree with Fuego that the redemptive purpose of Calvary was not finished at the crucifixion, but Jesus was stating that He had finished the work that the Father had sent Him to complete during His ministry years.
I think it was Colonel that mentioned Hebrews 2:9 which states:
But we do see Him who has been made a little while lower than the angels,
namely, Jesus, because of the suffering of death crowned with glory and honor,
that by the grace of God He might taste death for everyone.
Jesus mentioned to the 12 that the purpose of His death was to "give His life a ransom for many" (Mark 10:45).
This essentially means His death was to pay the price to free the lives of others.
Romans 6:23 says that the "wages of sin is death." This is in fact not only relating to a physical death, but spiritual death as a final outcome. But Jesus paid the ransom satisfying the wrath of God for the penalty of sin that has beset the entire human race from its inception in the garden.
That still leads to the question when exactly was the ransom paid or fully completed? On the cross alone? Or a combination of both, on the cross and in hades.
Getting back to Hebrews 2:9 says, "He is crowned with glory and honor." His exaltation is a result of His suffering and death; the cross led to the crown.
God's gracious purpose in it all was that Christ might taste death for everyone. The Savior died as our Representative and as our Substitute. The main controversy involves was only a physical death upon the cross enough to satisfy the divine claims of justice. Jesus died as a man (sinless) and He died for man. The majority of theology says the Lord bore in His body on the cross all God's judgement against sin so that those who believe on Him will never have to bear it (condemnation).
The argument still in effect is did Jesus taste death for everyone on the cross alone (physical) or did the ramifications of taking on the penalty of the human race sin also affect Jesus spirit after He descended into hades? Apparently it did because Paul wrote in 1 Timothy 3:16 that Jesus was justified in Spirit before He was taken up in glory. Justify means to declare righteous, to declare to be in the right, to vindicate. Jesus was totally righteous, without sin, and blameless in spite of the Pharisee's accusations. But Paul makes the claim that Jesus was justified in Spirit after the cross and after the resurrection. The awful penalty of taking on the entire human race sin affected Jesus entire being, spirit, soul and body. Was He born-again? I can honestly say I really don't have a clue. But when Jesus was raised from the dead, He was raised in a glorified body that had never existed before. He is indeed the first born from the dead and we shall be like Him because we shall see Him just as He is (1 John 3:2).