Cyrus of Persia let the Jews go home from Babylon to rebuild the temple. They laid the foundation with shouting and weeping (Ezra 3:10–13), then opposition hit and the work stopped (Ezra 4:4–5, 24). Roughly fifteen years later, about 520 B.C., the prophets Haggai and Zechariah stirred them up (Haggai 1:1; Ezra 5:1). Haggai’s charge was blunt: you live in paneled houses while the Lord’s house lies in ruins (Haggai 1:4). Consider your ways: you sow much and harvest little, and your wages go into “a bag with holes” (1:5–6). The people, led by Zerubbabel the governor and Joshua the high priest, went back to work, and the temple was finished about four years later (Ezra 6:15). Centuries later, enlarged by Herod, it was the temple where Jesus taught. The Lord gave the early Saints a similar rebuke when they delayed the Kirtland Temple (Doctrine and Covenants 95:3–8).
Zechariah adds visions and some of the clearest Messianic prophecies in the Old Testament. In chapter 3, Joshua the high priest stands in filthy clothes while Satan accuses him; the Lord has the filthy garments removed, clothes him in clean raiment and puts a clean turban (a “fair mitre”) on his head. It is a picture of what only the Savior can do for us. In chapter 4 the Lord tells Zerubbabel the temple will be finished “Not by might, nor by power, but by my spirit” (4:6), and asks who would despise “the day of small things” (4:10). Zechariah also foresaw the King riding on a donkey (9:9; Matthew 21:1–11), thirty pieces of silver (11:12–13; Matthew 26:14–15; 27:3–7), the one who was pierced (12:10; John 19:34–37), the smitten Shepherd (13:7; Matthew 26:31) and the wounds in His hands shown at His Second Coming (13:6; Doctrine and Covenants 45:51–52).
The phrase to build today around is Zechariah 14:20: in that day even the bells on the horses and the cooking pots will be inscribed HOLINESS UNTO THE LORD. Latter-day Saint temples carry those words, and Zechariah pictures them on the most ordinary objects of daily life. For 16- to 18-year-olds, that is the bridge to the endowment. Many of them will receive it within a year or two, before a mission or a temple marriage. The Church’s page “About the Temple Endowment” openly explains that endowed members covenant to live the law of obedience, the law of sacrifice, the law of the gospel, the law of chastity and the law of consecration, and receive the temple garment as a reminder. You can talk about those covenants plainly. Do not go beyond what the Church publishes, and point deeper questions to parents, the bishop and the temple preparation course.
Keep today honest and practical. Teens have real, good things competing for their time: school, work, sports, friends, screens. Haggai never tells the people to stop farming or building homes; he tells them to put the Lord’s house first and watch what happens to everything else.