Emily Dickinson, in a most bold and zealous fashion, has set forth for us in "Truth is as old as God" her deeply rooted beliefs in truth. She does not sway in her stance. Her beliefs are strong and precise and perhaps that is what makes this poem so easy to relate to and understand.
How much older can one get than God? Truth has been around forever and Emily feels it always will. In her comparison of Truth and God, she elevates the status of Truth to God-like qualities. In fact she says that Truth is God's twin identity. In these words we can see Emily's humility, or even reverence for Truth.
Then, however, Emily takes a turn on us. It begins to seem as if Emily is implying that God is finite; yet if one looks closely at the words it becomes clear that she is saying that none of that could ever happen. Truth cannot perish. God will not be borne away. Emily believes that Truth is absolute. Neither time nor Man can alter it.
The one point to which I am clueless is the final line. I can synthesize that it follows the general intent of the preceding lines, but I can not come to a conclusion as to exactly what she is intending . Is she saying Truth is the giver of life? I do not know.
Eight lines and she has, firmly, expressed her beliefs about Truth. Her uncompromising attitude towards her beliefs help us, and demands us, to understand what she is saying. She does not falter, and holds our hands as to insure that we don't falter in understanding Truth.