This is the key section of the entire discourse in Mark chapter 13. In Mark 13: 5-23 the evangelist mentioned certain events such as wars, famines, persecutions, abomination of desolation, great tribulation and the appearance of false Christs and false prophets. These historical events he presented as signs that precede the Parousia although in themselves they do not determine the exact time of the Parousia. In Mark 13: 24-27 the evangelist describes the coming of the Son of Man which will transcend the historical dimensions of the preceding events and which will occur after those days of unparalleled tribulation (cf. Mk 13: 19, 24a). The imagery and language of Mark 13: 24-27 are almost entirely drawn from the Old Testament and Jewish apocalyptic writings. However, there is no reference here to the overthrow of Satan or Anti-Christ (cf. Apoc 20: 10; 2Thess 2: 8) or to the judgement of the world (cf. Mt 25: 31-46). But the coming of the Son of Man is solely for the redemption of the elect (Mk 13: 27). This is the message of hope for Christians who eagerly awaited the return of the Lord.
Mark 13: 24-27 mentions three specific events: the cosmic phenomena (Mk 13: 24-25), the coming of the Son of Man (Mk 13: 26), and the gathering of the elect (Mk 13: 27). The Parousia of the Son of Man follows the period of hardships and tribulation. Apparently the evangelist himself regarded the Parousia to be imminent and therefore he does not specify an interval between the tribulation (cf. Mk 13: 19-20) and the Parousia (Mk 13: 24-27). According to Mark 13: 24, the cosmic signs which accompany the Parousia will appear “in those days, after that tribulation.” The expression “in those days,” which is a stereotyped formula of the Old Testament (cf. Jer 3: 18; 31: 29; Joel 3: 1), does not have a specific temporal value in itself. In Mark 13: 24, it points to a period subsequently to the days of tribulation. The description of the cosmic phenomena in Mark 13: 24-25 is clearly based on the prophetic and later Jewish apocalyptic writings (cf. Is 13: 10; 34: 4; Ezek 32: 7-8; Joel 2: 10; 3: 15, etc). The dissolution of the cosmos or catastrophic upheavals in the heavens formed part of the prophetic and apocalyptic descriptions of the “day of the Lord,” of Yahweh’s theophany on the “day of the Lord.” It is in this language and imagery that Mark 13: 24-27 presents the coming of the Son of Man.
The key statement about the Parousia is found in Mark 13: 26 which is itself influenced by Daniel 7: 13-14. “They will see the Son of Man coming in clouds with great power and glory.” This is the definitive manifestation of the Son of Man who possesses heavenly glory and power. Although the Son of Man had already manifested his authority on earth (cf. Mk 2: 10, 28), he was not perceived in his fullness of power. Jesus had also announced that he, as the Son of Man, was destined to be rejected, to suffer, die and rise again for the redemption of man (cf. Mk 8: 31; 9: 9, 12, 31; 10: 33-34, 35). At this Parousia the Son of Man will be vindicates and revealed in all his glory (Mk 13: 26; cf. Mk 8: 32; 14: 62). It is not for judgement that the Son of Man will come but “to gather his elect from the four winds, from the extremities of the earth” (Mk 13: 27). Mark 13: 27 also reflects the Old Testament expectation that God would gather the dispersed Israel and bring them back to their own land (cf. Deut 30: 3-4; Is 11: 12; Jer 23: 3; Ezek 11: 17; 20: 34, 41, etc). However, at his Parousia the Son of Man will send out his angels and gather together not the dispersed Israel, but his elect, the new Israel, those who believe in Christ and who are scattered throughout earth. Thus the comforting and consoling message for those who belong to Christ is that the glorious Son of Man will come in the clouds to gather his chosen and faithful people scattered throughout the earth.