The New Testament Greek Lexicon
| Strong's Number: 5760||Tense, Voice and Mood|
The perfect tense in Greek corresponds to the perfect tense in English, and describes an action which is viewed as having been completed in the past, once and for all, not needing to be repeated.
Jesus' last cry from the cross, TETELESTAI ("It is finished!") is a good example of the perfect tense used in this sense, namely "It [the atonement] has been accomplished, completely, once and for all time."
Certain antiquated verb forms in Greek, such as those related to seeing (eidw) or knowing (oida) will use the perfect tense in a manner equivalent to the normal past tense. These few cases are exception to the normal rule and do not alter the normal connotation of the perfect tense stated above.
The Greek infinitive mood in most cases corresponds to the English infinitive, which is basically the verb with "to" prefixed, as "to believe."
Like the English infinitive, the Greek infinitive can be used like a noun phrase ("It is better to live than to die"), as well as to reflect purpose or result ("This was done to fulfil what the prophet said").
Thayer and Smith. "Greek Lexicon entry for ". "The New Testament Greek Lexicon".