According to one opinion in the Talmud (Yevamot 62a), the reason for the mitzva of procreation is to hasten the coming of Moshiach: "The son of David will not come until all the souls in heaven have been born." Every time another child is born to the Jewish people, the coming of Moshiach is thereby hastened. Thus, every Jewish wedding is considered, in a sense, the beginning of the Redemption, for the couple will soon have children, and will thus hasten the coming of Moshiach.
(The Journal of Halacha Vol. 4 by Rabbi H. Schachter)