28 After this, Jesus, knowing that all was now finished, said (to fulfill the Scripture), “I thirst.” 29 A jar full of sour wine stood there, so they put a sponge full of the sour wine on a hyssop branch and held it to his mouth. 30 When Jesus had received the sour wine, he said, “It is finished,” and he bowed his head and gave up his spirit. ESV
In verse 28 the KJV has "accomplished" and in verse 30 "finished." The ESV above has "finished" in both instances. The same root verb teleo is used 2x in John at 19:30 and also verses 19:28 to form tetelestai. In vs. 28 it is in the aorist and in vs. 30 the perfect indicative (NA 27). This word appears over 28 times in the Greek New Testament (Matthew 7x; Revelation 8x; Luke 4x; Acts 1x; John 2x; Romans 2x and 1x in 2 Corinthians, Galatians, 2 Timothy and James).
Some often connect the word for "finished" with the idea of "paid in full". This word has a secondary use in ancient commerce to indicate a bill was paid in full. Although the Greek word here does have use in commerce it also has use in a number of different contexts (tax collection, marriage, citizenship). Yet, it seems unlikely that Christ has in mind the sense of money or payment when He uttered those words. In reality the most plain meaning of the word is "to complete, to finish, to end, to accomplish." These are perhaps the most common usages of the word.
Notice that by saying "It is finished" Jesus is referring to an action completed in the past. However, the perfect tense usually refers to completed action and continuing results. The sense of completeness in this word comes from the usage of the grammatical tense of the verb teleo, not the word itself, which simply means to finish or complete. Some grammarians such as Ernest D.W. Burton or H.P.V. Nunn cite John 19:30 as an example of using the pluperfect tense. (1) Ultimately, the context helps decide the tense of the verb. The pluperfect tense is almost the same as the perfect tense but brings the results up to a time in the past.
The results of Christs death, burial and resurrection have infinite results for believers yet as Jesus also stated in Luke 22:37 "the things concerning me have an end." (KJV) Mark 10:45, Matthew 20:28 and 26:28 indicate that while on earth Jesus understood His death and viewed it as a "ransom for many" (KJV) In John 13:1 Jesus had also told the disciples that His "hour had come" and "having loved his own who were in the world, he loved them to the end." (ESV) "It is finished" could more closely mean then "the prophetic portraiture of Messiah had been realized"(2). It was His "obedience unto death, even the death of the cross" (Philippians 2:8 KJV).
Also in 19:28 Jesus understands this in terms of accomplishing and completing the work of the Father. He had indicated earlier in John that when the Father is working now, He is working now (John 5:17). It is by the work of Jesus that the Father and Son work and are glorified not because they are separate persons but because of the completed work done in God's plan. Christ raised Himself from the dead after three days so while the plan of God was not entirely exhausted particular plans of God for the Messiah had been completed.
Τετέλεσται [tetelestai] is accordingly a significant expression of the theological intentions of the Evangelist, who views Jesus’ death as God’s victory.(3)Atonement:
The Bible perhaps does not teach any one theory of Atonement. The Bible teaches that Christ has taken our place and by doing so has done for us what we could not do for ourselves. From the Scriptures we can know that we have been redeemed and that a price has been paid. In the Garden of Eden the first Adam sinned against God, not Himself. Animal sacrifices will not suffice or satisfy (Hebrews 10:4). Christ is the perfect sacrifice which paid sins penalty (Hebrews 9:26; Romans 3:25-26, 6:23; Galatians 3:13).
Because of His, once for all, sacrifice believers are redeemed by Christ (Ephesians 1:7). As believers we are bought with a price (1 Corinthians 6:20). We are justified through the redemption that is in Christ, who God put forward as a propitiation by his blood (Romans 3:24-25). God did not remain remote and lofty but came Himself, and forgave us Himself. The death of Jesus is God's victory. Not because Jesus and God are separate or separate persons but that in a real way God has personally and substantively acted in the world.
Jesus is God (John 1:1, 14; 2 Peter 1:1) and therefore it is rightly said that God purchased the Church with His own blood (Acts 20:28). The work of Jesus is God's work. As God, according to the flesh (Romans 9:5), Peter can say we are "Redeemed...with the precious blood of Christ." (1 Peter 1:18-19) and later "Feed the flock of God" (1 Peter 5:2). Because his God was the same One God that Thomas called "Lord" and "God" as he beheld the Resurrected Lord of Glory (John 20:28; cf. 1 Corinthians 2:8).
1) Ernest De Witt Burton, Syntax of the Moods and Tenses in New Testament Greek, 3rd ed. (Edinburg: T&T Clark, 1898). 23. - H. P. V. Nunn, A Short Syntax of New Testament Greek (Cambridge: Cambridge University Press, 1920). 72.
2) Brooke Foss Westcott and Arthur Westcott editors. The Gospel According to St. John Introduction and Notes on the Authorized Version, Classic Commentaries on the Greek New Testament (London: J. Murray, 1908). 277."
3) Horst Robert Balz and Gerhard Schneider editors, Exegetical Dictionary of the New Testament (Grand Rapids, Mich.: Eerdmans, 1990-). 347.