What does it mean? Literally translated the word tetelestai means “it is finished”. The word occurs in John 19:28 and 19:30 and these are the only two places in the New Testament where it occurs. In 19:28 it is translated “After this, when Jesus knew that all things had been accomplished, in order that the scripture might be fulfilled Jesus said “I am thirsty”. Two verses later He utters the word Himself: “Then when he had received the sour wine Jesus said, “It is finished” and He bowed His head and gave up His spirit”.
The word tetelestai was also written on business documents or receipts in New Testament times to show that a debt had been paid in full.
The Greek-English lexicon by Moulton & Mulligan says this:
“Receipts were often introduced by the phrase [sic} tetelestai , usually written in an abbreviated manner…” (p. 630) the connection between receipts and what Christ had accomplished would have been quiet clear to John’s Greek speaking readership; it would have been unmistakable that Jesus Christ had died to pay for their sins.