The spiritual ebb and flow of life is described in the poem "Love Thou Thy Land" by Alfred, Lord Tennyson , where this quote comes from. Tennyson believed that human nature would assert its wholeness in civilized man.
He also believed that there must come a time, in the progress of civilization, when this ebb and flow will be less marked than before , by reason of a better balancing, which will be brought about, of the intellectual and the spiritual. Each will have its due activity.
A man of intellectual pursuits such as Tennyson, did not want to have a starved spiritual nature; and this poet of predominant spiritual functions did not want not to have an intellect weakened into a submissiveness to formulated, stereotyped, and, consequently, lifeless dogmas.