"faith . . . can save even without the sacrament"

"Therefore let us open our eyes and learn to pay heed more to the word than to the sign, more to faith than to the work or use of the sign. We know that wherever there is a divine promise, there faith is required, and that these two are so necessary to each other that neither can be effective apart from the other. For it is not possible to believe unless there is a promise, and the promise is not established unless it is believed. But where these two meet, they give a real and most certain efficacy to the sacraments. Hence, to seek the efficacy of the sacrament apart from the promise and apart from the faith is to labor in vain and to find condemnation. Thus Christ says: 'He who believes and is baptized will be saved; but he who does not believe will be condemned' [Mark 16:16]. He shows us in this word that faith is such a necessary part of the sacrament that it can save even without the sacrament [(Quo monstrat, fidem in sacramento adeo necessarium, ut etiam sine sacramento servare possit)], and for this reason he did not add: 'He who does not believe, and is not baptized.'"

     Martin Luther, The Babylonian captivity of the church (1520), LW 36, 67 =WA 6:533 l. 37-534 l. 1.
     But according to Bryan D. Spinks ("Luther’s timely theology of unilateral baptism," Lutheran quarterly 9, no. 1 (Spring 1995): 31-32 (23–45)):  "However, when we inquire as to what Luther here means by faith, we have a very interesting answer.  It appears to be no more than accepting that in this sacrament God will do what he says he does"; "by 'faith' Luther here simply means acceptance that God will grant justification and salvation through this strange ritual" (all underscoring and italics mine).
 

     "Therefore the rule of which I have also spoken above stands. It states that God no longer wants to act in accordance with His extraordinary or, as the scholastics express it, absolute power but wants to act through His creatures, whom He does not want to be idle. . . .  This they call God’s 'ordered' power, namely, when He makes use of the service either of angels or of human beings. . . .
     "But if at times some things happen without the service either of angels or of human beings, you would be right in saying: 'What is beyond us does not concern us.' We must keep the ordered power in mind and form our opinion on the basis of it.  God is able to save without Baptism, just as we believe that infants who, as sometimes happens through the neglect of their parents or through some other mishap, do not receive Baptism are not damned on this account. But in the church we must judge and teach, in accordance with God’s ordered power, that without that outward Baptism no one is saved. Thus it is due to God’s ordered power that water makes wet, that fire bums, etc. But in Babylon Daniel’s companions continued to live unharmed in the midst of the fire (Dan. 3:25). This took place through God’s absolute power, in accordance with which He acted at that time; but He does not command us to act in accordance with this absolute power, for He wants us to act in accordance with the ordered power."

     Martin Luther, Lectures on Genesis (1535-1545) 19:14, LW 3, 274, underscoring mine =WA 43, 71 ll. 7 ff.