Zechariah 12:10 is truly one of the most amazing scriptures in the Old Testament. This one verse foretells the crucifixion of Jesus the Messiah, the fact that He would be rejected by the Jews, and His second coming when they will look upon the one they have pierced:
10 "And I will pour out on the house of David and the inhabitants of Jerusalem a spirit of grace and supplication. They will look on me, the one they have pierced, and they will mourn for him as one mourns for an only child, and grieve bitterly for him as one grieves for a firstborn son."
There is a ton of GREAT stuff at the end of the "Old Testament". If you have not read some of those books lately, then I would HIGHLY recommend it.