The great secret and central fact of the universe is that there exists a Spirit (Intelligent Energy) of Infinite Life and Power that is back of all, that animates all, and from which all comes. And to the degree that we come to a realization of this Infinite Source and learn to connect ourselves with it, do we make it possible for this power to work within us, to manifest through us.
What you call this "Infinite Source" or "Intelligent Energy" is up to you. But there is no denying that it exists. It is where Your Life Power comes from, for you to use (or not use) as you choose.
"I hold it as a changeless law
From which no soul can sway or swerve,
We have that in us which will draw
Whate'er we need or most deserve."
-- Ella Wheeler Wilcox,
Poems of Power (1910)