St. Augustine on Veneration to the Saints
It is true that Christians pay religious honor to the memory of the martyrs, both to excite us to imitate them and to gain a share in their merits and the assistance of their prayers. Yet we do not build altars to any martyr, but to the God of martyrs, although it is to the memory of the martyrs. No one presiding at the altar in the saints’ burial place ever says, “We bring an offering to you O Peter!” or “O Paul!” or “O Cyprian!” The offering is made to God, who gave the crown of martyrdom, while it is in memory of those thus crowned.
The emotion is increased by the associations of the place, and love is excited both toward those who are our examples, and toward him by whose help we may follow such examples. We regard the martyrs with the same affectionate intimacy that we feel towards holy men of God in this life, when we know that their hearts are prepared to endure the same suffering for the truth of the Gospel. There is more devotion in our feeling toward the martyrs, because we know that their conflict is over; and we can speak with greater confidence in praise of those already victors in heaven, than of those still combating here.
What is properly divine worship, the Greeks call latria (for which there is no word in Latin), and both in doctrine and in practice we give this only to God. To this [divine] worship belongs the offering of sacrifices, as we see in the word “idolatry,” which means the giving of this worship to idols. Accordingly we never offer, or require anyone to offer, sacrifice to a martyr, or to a holy soul, or to any angel. Anyone falling into this error is instructed by doctrine, either in the way of correction or of caution. For holy beings themselves, whether saints or angels, refuse to accept what they know to be due to God alone. We see this in Paul and Barnabas, when the men of Lycaonia wished to sacrifice to them as gods, on account of the miracles they performed. They rent their clothes, and restrained the people, crying out to them, and persuading, them that they were not gods. We see it also in the angels, as we read in the Apocalypse that an angel would not allow himself to be worshipped, and said to his worshipper, “I am your fellow-servant, and of your brethren” (Rev 19:10).
-St. Augustine of Hippo, 4th Century