He that believeth and is baptized shall be saved; but he that believeth not shall be damned.
”…there is still one more thing here, that Christ says: “He that believeth and is baptized shall be saved.” Here you might say: I perceive, then, that baptism is also required. To be sure it is, but baptism is not a work that we do. It is to be coupled, however, with faith, because God would not have faith to be hidden in the heart, but would have it burst forth and manifest itself to the world.
“For this reason he ordained such outward signs, by means of which everyone may show and confess his faith, to the end that we may come to the holy cross. For, if faith were to be kept as a secret, hidden in the heart, we would be pretty sure of not having to bear the cross or to follow Christ; if the world knew not that we believed, we would not be persecuted.
From Martin Luther’s Church Postil, Lenker Edition Vol. 3, “Day of Christ’s Ascension Into Heaven.”