On Infant Baptism from the Large Catechism

Here we further assert, that it is not of the greatest importance as to this point, whether the person baptized believes or does not believe; for Baptism does not become wrong on this account, but all depends upon the word and command of God. Now this is indeed a nice point, but it is founded upon the assertion, that Baptism is nothing else than water and the word of God intimately united; that is, when the word is connected with the water, then baptism is right, although the individual may be destitute of faith at the time of his baptism; for my faith does not make, but it receives Baptism. Now Baptism does not become wrong, even if it be wrongly received and applied, since, as observed above, it does not depend on our belief, but upon the word of God....

For this reason we say, if you have not believed, believe yet, and thus declare: "The baptism was surely right, but I alas! have not received it rightly." For I myself, and all who permit themselves to be baptized, must thus say before God: "I come hither in my faith and that of others, yet I cannot depend on my belief and the prayers of many others for me, but I rely on thy word and command, even as I go to the sacrament of the Lord's Supper, not upon my faith, but upon the words of Christ, whether I be strong or weak, for this I let God provide; but I know that he orders me to go, to eat, and to drink, &c., and that he gives me his body and his blood,– which words will neither belie nor deceive me."