[quote=Fidelis]Since this is usually said right after the invocation of the Trinity, the “it” being refered to is the eternal God in Three Persons, whom this prayer glorifies. The “world without end” is a poor translation of the original “for generation upon generation” or something similar.
Thus, it can be rendered: "Glory be to the Father, and to the Son, and to the Holy Spirit; as it was in the beginning, is now, and ever shall be, throughout all generations. Amen
I could be mistaken, but I think it is equivalent to a phrase that is found over and over again in the Wisdom literature of the Bible: “from everlasting to everlasting” (I think the Orthodox use a phrase close to this). In essence, it means for all eternity.