13:24 in those days. Since this is a technical Old Testament term for the last days (Jer. 3:16; Joel 3:1; Zech. 8:23), Jesus may be starting to speak of the end (cf. v. 7). According to some interpreters, in v. 26 the Second Coming is in view.
the sun will be darkened. Although these phrases often refer to the time of God’s cosmic and final judgment (Is. 13:10; 34:4; Joel 2:10, 31), here they may signify another event so momentous that after it the world will never be the same again. Peter interprets Joel 2:31 in Acts 2:16–21 as a prophecy of the outpouring of the Spirit at Pentecost.