Like it or not, the Old Testament says no such thing.
So you don't have to accept it.
But the question is what Christians are supposed to believe. Jorge's point is that, if Christians do not proselytize among Jews, they will be denying their own beliefs -- or at least what they claim are their beliefs.
Like it or not, the Old Testament says no such thing.
For starters:
Zechariah
Chapter 10
1: The burden of the word of the LORD for Israel, saith the LORD, which stretcheth forth the heavens, and layeth the foundation of the earth, and formeth the spirit of man within him.
2: Behold, I will make Jerusalem a cup of trembling unto all the people round about, when they shall be in the siege both against Judah and against Jerusalem.
3: And in that day will I make Jerusalem a burdensome stone for all people: all that burden themselves with it shall be cut in pieces, though all the people of the earth be gathered together against it.
4: In that day, saith the LORD, I will smite every horse with astonishment, and his rider with madness: and I will open mine eyes upon the house of Judah, and will smite every horse of the people with blindness.
5: And the governors of Judah shall say in their heart, The inhabitants of Jerusalem shall be my strength in the LORD of hosts their God.
6: In that day will I make the governors of Judah like an hearth of fire among the wood, and like a torch of fire in a sheaf; and they shall devour all the people round about, on the right hand and on the left: and Jerusalem shall be inhabited again in her own place, even in Jerusalem.
7: The LORD also shall save the tents of Judah first, that the glory of the house of David and the glory of the inhabitants of Jerusalem do not magnify themselves against Judah.
8: In that day shall the LORD defend the inhabitants of Jerusalem; and he that is feeble among them at that day shall be as David; and the house of David shall be as God, as the angel of the LORD before them.
9: And it shall come to pass in that day, that I will seek to destroy all the nations that come against Jerusalem.
10: And I will pour upon the house of David, and upon the inhabitants of Jerusalem, the spirit of grace and of supplications: and they shall look upon me whom they have pierced, and they shall mourn for him, as one mourneth for his only son, and shall be in bitterness for him, as one that is in bitterness for his firstborn.
11: In that day shall there be a great mourning in Jerusalem, as the mourning of Hadadrimmon in the valley of Megiddon.
12: And the land shall mourn, every family apart; the family of the house of David apart, and their wives apart; the family of the house of Nathan apart, and their wives apart;
13: The family of the house of Levi apart, and their wives apart; the family of Shimei apart, and their wives apart;
14: All the families that remain, every family apart, and their wives apart.