We can infer the oneness of God from the creation of the universe, because the universe is a work connected together as one thing from beginning to end, all dependent on one God as the body depends on its soul. The universe was designed to allow God to be omnipresent, keep every detail of it under his supervision, and maintain it perpetually as one entity, that is, preserve it.
This is why Jehovah God says he is “the First and the Last, the Beginning and the End, the Alpha and the Omega” (see Isaiah 44:6; Revelation 1:8, 17); and why he says elsewhere that he makes all things, stretches out the heavens, and extends the earth by himself (see Isaiah 44:24).
This vast system called the universe is a work connected as one thing from beginning to end because God had a single purpose in creating it: an angelic heaven populated by the human race. All the things that make up the world are means of fulfilling that purpose, because someone who intends an end result also intends the means to achieve it.
from True Christianity, Volume 1, Page 18