2 Samuel 6:4

"Again I say to you, if two of you agree on earth about anything they ask, it will be done for them." Strictly speaking, the word symphony is used by musicians for the voices of harmony. For among musical tones, some harmonize with each other and others do not. But the Gospel is also familiar with this term as applied to music where it says, "He heard music [symphōnias] and dancing." For it was fitting that, at the harmony that resulted between the father and his son who had been lost but was now found through his repentance, a symphony should be heard on the occasion of the rejoicing of the house.… Akin to this kind of symphony is what is written in the second book of Kings [Samuel] when the brothers of Aminadab "went before the ark, and David and the sons of Israel were playing before the face of the Lord on well-tuned instruments and in power and in songs." For the "well-tuned instruments in power and in song" have in them that harmony of tones which is of such power that if only two people bring before the Father in heaven any request with that symphony which is found in divine and spiritual music, the Father grants it to them—which is most remarkable.