God's Plan Has Been In Process, Jesus' Work Is Now Finished, And It Will Remain Finished, with Continuing Effects (Greek Perfect Tense, Koine)
The Greek Perfect Tense in the Bible is only used a handful of times in the New Testament; and unlike our English verb tenses, the Greek perfect tense holds three layers of meaning within it's form.
One way of stating the full meaning of the perfect tense is this: it is both punctiliar and linear, or, in other words, it is both happening at a point and time (punctiliar) and ongoing in time (linear).
I also like to describe the perfect tense verb as having 3 layers of meaning all within the one word.
1st layer - The action has been in process.
2nd layer - The action has just been completed.
3rd layer - The action will remain completed, with its continuing effects.
When it was written that Jesus said "Tetelestai," the word tetelestai, the Greek word for "finished" or for "fulfilled" was written in the rare perfect tense.
Let's look at the layers:
1st layer - Jesus' work has been in process of being finished.
2nd layer - Jesus' work is now completed. His work is finished.
3rd layer - This completion will remain completed, with continuing effects.
"It is finished" is 3 words sharing 3 layers of truth. The work and the purpose of Christ had been in process. Christ's work was finished at his last words on the cross. His work will remain finished, along with its continuing effects.
(One other time the perfect tense was used in the New Testament was when Jesus announced the nearing of the kingdom of God at the very beginning of His ministry. It was his first teaching we have written down in the New Testament. I wrote a blog about that teaching and the perfect tense HERE.)
Long ago in the year 1686, Matthew Henry began preaching. He was 24 years old, and he continued to preach and to pour over scripture - word by word and phrase by phrase - until his death at the age of 51. Henry wrote this in response to Jesus' last spoken word on the cross: