Paul McCain quotes Luther:
“The invocation of the saints is also one of the Antichrist’s abuses that conflicts with the chief article and destroys the knowledge of Christ (Philippians 3:8). It is neither commanded nor counseled, nor has it any warrant in Scripture. Even if it were a precious thing–which it is not–we have everything a thousand times better in Christ. The angels in heaven pray for us, as does Christ Himself. So do the saints on earth, and perhaps also in heaven. It does not follow though that we should invoke and adore the angels, and saints. Nor should we fast, hold festivals, celebrate Mass, make offerings, and establish churches, altars, and divine worship in their honor. Nor should we serve them in other ways of regard them as helpers in times of need. Nor should we divide different kinds of help among them, ascribing to each one a particular form of assistance, as the papists teach and do. This is idolatry. Such honor belongs to God alone. As a Christian and saint upon earth, you can pray for me in many necessities. But this does not mean that I have to adore and call upon you. I do not need to celebrate festivals, fast, make sacrifices, or hold Masses for your honor. I do not have to put my faith in you for my salvation. I can honor, love, and thank you in Christ in other ways. If such idolatrous honor were withdrawn from angels and departed saints, the remaining honor would be harmless and quickly forgotten. When advantage and assistance (both bodily and spiritual) are no longer expected, the saints will not be troubled, neither in their graves nor in heaven. No one will much remember or esteem or honor them without a reward or just out of pure love.”
Smalcald Articles, Part I, Article II, par.25-28.
Concordia: pgs. 292-293.