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
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.