Zechariah 7:12
7:12 Indeed, they made their heart as hard as diamond, 1 so that they could not obey the Torah and the other words the Lord who rules over all had sent by his Spirit through the former prophets. Therefore, the Lord who rules over all had poured out great wrath.
Zechariah 14:4
14:4 On that day his feet will stand on the Mount of Olives which lies to the east of Jerusalem, and the Mount of Olives will be split in half from east to west, leaving a great valley. Half the mountain will move northward and the other half southward. 2
1 tn The Hebrew term שָׁמִיר (shamir) means literally “hardness” and since it is said in Ezek 3:9 to be harder than flint, many scholars suggest that it refers to diamond. It is unlikely that diamond was known to ancient Israel, however, so probably a hard stone like emery or corundum is in view. The translation nevertheless uses “diamond” because in modern times it has become proverbial for its hardness. A number of English versions use “flint” here (e.g., NASB, NIV).
2 sn This seismic activity provides a means of escape from Jerusalem so that the Messiah (the Lord), whose feet will stand on the Mount of Olives, may destroy the wicked nations in the Kidron Valley (the v. of Jehoshaphat, or of “judgment of the Lord”) without harming the inhabitants of the city.