When Dover Beach begins, the reader is drawn to the image of the cliffs and even lulled into a false sense of security, expecting Arnold to enjoy the moment as "sweet is the night-air!" He then proceeds and is almost issuing a warning - "Listen" - that appearances are deceiving because when you stop and actually listen to the "grating" you will be affected by "The eternal note of sadness." The situation exists between the speaker and his "love" whom he implores to "be true To one another" implying that there is no-one else. They only have each other.
On the other hand, Toplady has his conversation with God and does not worry because "Blest be the tempest, kind the storm" and he is confident that it will serve to "drive us nearer home." Any fears that "we" have will be moderated as we " all yield to Thy control." There is a clear understanding that Toplady speaks for others as we "make Thy will our own. "
Arnold did have his faith at one point "But now I only hear
Its melancholy" and he is unable to reconcile himself with "The Sea of Faith." Arnold is warning his "love" that the world may appear to be a "land of dreams" but actually on reflection "we" are "Swept with confused alarms of struggle and flight" where there is "neither joy, nor love, nor light,... nor peace, nor help for pain" such as a person can expect if they have faith in God. He is however "on a darkling plain." He can see no future
By complete contrast, Toplady is humble in his praise of God to "teach us" and surely then "Thy tender mercies shall illume The midnight of the soul." Toplady may not know what lies in store for the future but he is confident and content "To live by faith alone."