Origen

“ And strictly, indeed, concord takes place in two things generic, through the perfecting together, as the Apostle has called it, of the same mind by an intellectual grasp of the same opinions, and through the perfecting together of the same judgment, by a like way of living. ”

“ The Power of Harmony in Relation to Prayer.
“Again I say unto you that if two of you shall agree [1] on earth as touching anything that they shall ask, it shall be done for them.” [2] The word symphony is strictly applied to the harmonies of sounds in music. And there are indeed among musical sounds some accordant and others discordant. But the Evangelic Scripture is familiar with the name as applied to musical matters in the passage, “He heard a symphony and dancing.” ”

“ But he who has the power will consider whether this agreement and a congregation of this sort in the midst of which Christ is, can be found in more, since “narrow and straightened is the way that leadeth unto life, and few be they that find it.” [10] But perhaps also not even few but two or three make a symphony as Peter and James and John, to whom as making a symphony the Word of God showed His own glory. But two made a symphony, Paul and Sosthenes, when writing the first Epistle to the Corinthians; [11] and after this Paul and Timothy when sending the second Epistle to the same. ”