Zecharyah 12:10

And I will pour upon the Bais Dovid, and upon the inhabitants of Yerushalayim, the Ruach (Spirit) of Chen (grace) and of Tachanunim (supplications for favor); and they shall look upon Me whom they have pierced, and they shall mourn for Him (Moshiach) as one mourneth for his yachid (only son), and shall grieve in bitterness for him, as one that is in bitterness for his bechor (firstborn).