ἐκτελέσαι [2 verses](verb aor inf act) "To finish" is ekteleō , which means to "bring to an end", "accomplish", and "achieve", "fulfill" a promise, and in the passive, "will be accomplished". -- The word translated as "to finish" is uncommon and used for the first time here. It means to "bring to an end", "accomplish", and "achieve", "fulfill" a promise, and in the passive, "will be accomplished".  However, it is a form of a very common Greek word that means "to finish" or "fulfill" with the addition of a common prefix meaning "out of".