Clinging to oneness is a subtle form of violence against the Self. For if all phenomena are waves of the mirage in the empty sky of awareness, then nothing that happens could possibly remove you from the unity of the Self, and therefor no discipline or effort is required to hold on to it.
That very discipline, that very effort, breaks the continuum, the creaminess, of Brahman. For the world's phenomena are like streaks of cream in cream. Our very discipline, our very effort to avoid duality, confirms the duality and does violence to the One. Our effort churns the cream into lumps.
One ever celebrates as Two, and Two ever dissolves into One, and there is absolutely nothing to do about it.
Yet this is what the ego most dreads and hates to discover, because the restless mind wants constantly to work at some accomplishment.
Grace is discovering there is nothing to do. Nothing is more humiliating for our mind than Grace.