Psalms 121:6

"May the Lord shield thee upon the hand of thy right hand" (ver. 6). I have said, and I believe ye have recognised it. For had ye not recognised it, and that from the Scriptures, ye would not signify your understanding of it by your voices. Since then ye have understood, brethren, consider what followeth; wherefore the Lord shieldeth thee "upon the hand of thy right hand," that is, in thy faith, wherein we have received "power to become the sons of God," and to be on His right hand: wherefore should God shield us? On account of offences. Whence come offences? Offences are to be feared from two quarters, for there are two precepts upon which the whole Law hangeth and the Prophets, the love of God and of our neighbour. The Church is loved for the sake of our neighbour, but God for the sake of God. Of God, is understood the sun figuratively: of the Church, is understood the moon figuratively. Whoever can err, so as to think otherwise of God than he ought, believing not the Father and the Son and the Holy Ghost to be of one Substance, has been deceived by the cunning of heretics, chiefly of the Arians. If he hath believed anything less in the Son or in the Holy Spirit than in the Father, he hath suffered an offence in God; he is scorched by the sun. Whoever again believeth that the Church existeth in one province only, and not that she is diffused over the whole world, and whoso believeth them that say, "Lo here," and "Lo there, is Christ," as ye but now heard when the Gospel was being read; since He who gave so great a price, purchased the whole world: he is offended, so to speak, in his neighbour, and is burnt by the moon. Whoever therefore erreth in the very Substance of Truth, is burnt by the sun, and is burnt through the day; because he erreth in Wisdom itself ...God therefore hath made one sun, which riseth upon the good and the evil, that sun which the good and the evil see; but that Sun is another one, not created, not born, through whom all things were made; where is the intelligence of the Immutable Truth: of this the ungodly say, "the Sun rose not upon us." Whosoever erreth not in Wisdom itself, is not burnt by the sun. Whosoever erreth not in the Church, and in the Lord's Flesh, and in those things which were done for us in time, is not burnt by the moon. But every man although he believeth in Christ, erreth either in this or that respect, unless what is here prayed for, "The Lord is thy defence upon the hand of thy right hand," is realized in him. He goeth on to say, "So that the sun shall not burn thee by day, nor the moon by night" (ver. 6). Thy defence, therefore, is upon the hand of thy right hand for this reason, that the sun may not burn thee by day, nor the moon by night. Understand hence, brethren, that it is spoken figuratively. For, in truth, if we think of the visible sun, it burneth by day: doth the moon burn by night? But what is burning? Offence. Hear the Apostle's words: "Who is weak, and I am not weak? who is offended, and I burn not?"