“Nature is an Æolian Harp, a musical instrument; whose tones again are keys to higher strings in us.”

Harper of the Stones (1986).
Context: Again he struck the harp and began the jig. But this time it was such music as never came from a harp. It was the wildest, strangest music you ever heard, full of the sound of birds and the cries of animals and the wind and the rain, and the thunder and the lightning, and the dashing of huge waves against the shores of a great cold ocean that was formed from ice that had made its way slowly down from Ultima Thule. It was the sound of a world before mankind. It was the sound of the great merriment God must have known during the long days of Creation.

Gambara (1837)

Variant: There's nothing remarkable about it. All one has to do is hit the right keys at the right time and the instrument plays itself.

Read from his musical diaries while speaking at St. Vladimir’s Seminary https://vimeo.com/221011528/

Hymn 19, Hymns and Spiritual Songs, Book II.
Attributed from postum publications, Hymns and Spiritual Songs (1773)

A Picture Song.

Literary and Historical Miscellanies (1855), The Necessity, the Reality, and the Promise of the Progress of the Human Race (1854)
Context: The glory of God is not contingent on man's good will, but all existence subserves his purposes. The system of the universe is as a celestial poem, whose beauty is from all eternity, and must not be marred by human interpolations. Things proceed as they were ordered, in their nice, and well-adjusted, and perfect harmony; so that as the hand of the skilful artist gathers music from the harp-strings, history calls it forth from the well-tuned chords of time. Not that this harmony can be heard during the tumult of action. Philosophy comes after events, and gives the reason of them, and describes the nature of their results. The great mind of collective man may, one day, so improve in self-consciousness as to interpret the present and foretell the future; but as yet, the end of what is now happening, though we ourselves partake in it, seems to fall out by chance. All is nevertheless one whole; individuals, families, peoples, the race, march in accord with the Divine will; and when any part of the destiny of humanity is fulfilled, we see the ways of Providence vindicated. The antagonisms of imperfect matter and the perfect idea, of liberty and necessary law, become reconciled. What seemed irrational confusion, appears as the web woven by light, liberty and love. But this is not perceived till a great act in the drama of life is finished. The prayer of the patriarch, when he desired to behold the Divinity face to face, was denied; but he was able to catch a glimpse of Jehovah, after He had passed by; and so it fares with our search for Him in the wrestlings of the world. It is when the hour of conflict is over, that history comes to a right understanding of the strife, and is ready to exclaim: "Lo! God is here, and we knew it not."

Quoted in Interview with pianist Leon Fleisher http://www.examiner.com/article/interview-with-pianist-leon-fleisher by Elijah Ho (October 1, 2014)

Source: Titus Alone (1959), Chapter 42 (p. 881)