Among the Gospels, only Matthew’s Gospel uses the phrase “to the end of the age (sunteleia aiōnos)” (13:39, 40, 49; 24:3; 28:20). The phrase occurs also once in Hebrews (9:26), but in that context the qualifying noun is plural (aiōnōn), not singular. The only other occurrences of this phrase in contemporary Greek literature (according to TLG) occur in the Testament of Levi (10.2.2) and Testament of Benjamin (11.3), but in both cases those writers use the plural aiōnōn as the genitive modifier (cf. also 1 Enoch 16:1; Assumption of Moses 12:4; 4 Ezra 7:113; 2 Baruch 13:3; 19:5; 21:8; 27:15), in distinction from the usage in Matthew’s Gospel.
Both lexemes occur by themselves frequently in Greek literature, but not together as we find in Matthew’s Gospel. The fact that it only occurs otherwise in the Epistle to the Hebrews and also first century Jewish apocalyptic writings, indicates that it arose within Jewish communities and perhaps specifically Jewish Christian communities of the early first century AD. [Some also reference a phrase in the Latin 2 Esdras 7:113 that describes the end of the age (you can find this in the New Revised Standard Version with Apocrypha). While the Latin is based on a Greek version, the Greek text is lost and we only have quotations of it dated to the second century AD. As a result we do not know when this document was composed.]
The claim is made by various scholars that this phrase “is frequent in Jewish apocalyptic literature,” but this must be tempered with the fact that we are uncertain whether any of these Jewish apocalyptic writings, in the form that we have them today, existed in the time of Jesus or prior to the composition of the Gospel of Matthew (c. 70-75 AD). Matthew’s Gospel may be contemporaneous with some of these documents, e.g., the Testament of the XII Patriarchs, but this possibility does not help us understand its development and prior usage in Jewish discourse. So we have little to go on when it comes to tracing the usage of this phrase before the time of Jesus or the composition of Matthew’s Gospel. However, the use of the singular form of aiōn in the Matthew phrase distinguishes the phrase from its uses in Jewish apocalyptic literature. I mention these details to provide some guidance regarding comments that you may read in different commentaries on Matthew’s Gospel regarding this phrase.
The noun sunteleia does occur in the Septuagint text of Daniel as the translation of an Aramaic word that means “end” signifying the eschatological end (8:19). “Lo I am telling you what will take place at the end of the wrath against the sons of the people, for yet will remain the appropriate time of consummation (sunteleias).” At 12:13 the angel promises Daniel “you will rise upon your glory at the consummation (sunteleian) of days.” So the Greek translation of Daniel employed by some Jews in the first century used this noun with an eschatological sense. However, this noun has many other uses in the Septuagint. For example, it describes the end of the year in Deuteronomy 11:12 and 2 Chronicles 24:23. There do not seem to be any Hebrew phrases with similar meaning occurring within the Dead Sea Scrolls.
The use of this phrase in Matthew’s Gospel occurs in the discourse of Jesus or of his disciples (24:3). Jesus employs it in two parables (The Wheat and the Weeds 13:39-40; The Net 13:49), and in his last words to his disciples as he ascends (28:20). His disciples question Jesus about the “sign of your parousia and end of the age” in response to Jesus’ prophecy about the destruction of Jerusalem and the Temple (24:2-3). The singular “age” (aiōn) seems to refer to the period between the first and second comings of Jesus. In his teaching Jesus reveals what will be happening at “the end of this age” and assures his followers that he will be with them throughout “this age” (28:20).
The parables of The Wheat and Weeds and The Net are unique to Matthew’s Gospel. In all three Synoptic Gospels all or some of the disciples privately ask Jesus about his prophecy of judgment (Matthew 24:2-3; Mark 13: 2-4; Luke 21:6-7). In Mark’s version of this interchange the question is “what is the sign whenever all these things are going to be completed (sunteleisthai)” and the verb cognate to sunteleia occurs. Luke’s account uses neither the noun nor the verb, but rather has a more general question “what is the sign whenever these things are about to happen.” In Matthew’s account the disciples ask two questions: “when will these things be and what is the sign of your coming and end of the age.” So one of the questions regarding this phrase is whether Jesus himself employed it, or whether the author of Matthew’s Gospel is responsible for its occurrence. We cannot resolve this question here. However, if the phrase cannot be documented in Jewish documents prior to the time of Jesus, then perhaps it is reasonable to think that he might have coined it to suit his didactic purposes. Its occurrence in the two parables, unique to Matthew, might also support this hypothesis. The writer of Matthew may have extended its use in 24:3 in order to interpret the nature of the disciples’ question.
The phrase indicates that in the early Church key leaders viewed their current “age” as a finite period, to be consummated at the Parousia of Jesus Messiah. This “age” is bracketed by the two appearances of Jesus as Messiah and thus its sense and focus gets defined by his mission. When the “end of the age” occurs, the Messiah will hold every human who lived in this age accountable. In the course of this “age” the Messiah’s disciples will engage his mission and in the process experience serious opposition and suffering, but the Messiah promises to be present with them “until the end of this age.” His ascension does not portend his absence.