Repentance holds contrition and faith...

We have declared why we assigned these two parts, contrition and faith, to repentance.  We have done this willingly.  Many writings about repentance are published that cite the fathers in a butchered way,  The adversaries have distorted these to put faith out of sight.  Among these are, "Repentance is to lament past evils, and not to commit again deeds that ought to be lamented."  Again, "Repentance is a kind of vengeance of him who grieves, thus punishing in himself what he is sorry for having committed."  In these passages, no mention is made of faith.  Not even in the schools, when they interpret them, is anything added about faith.  Therefore, in order that the doctrine of faith might be clearer, we have named it among the parts of repentance. For experience shows that those passages are dangerous that require contrition or good works, and make no mention of justifying faith.  Caution can justly be desired in those who have collected these centos of the Sentences and decrees.  Since the Fathers speak in some places about one part of repentance, and in other places about another part, it would have been good to select and combine their judgement not only about one part but about both, that is, about contrition and faith.

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Therefore, there are sentences written by the Fathers not only about contrition and works, but also about faith.  But the adversaries, since they understand neither the nature of repentance nor the language of the Fathers, select passages about a part of repentance, namely, about works.  They overlook the declarations made elsewhere about faith, since they do not understand them.
~BOC, AP, XII (V), 91-93, 97

Faith in Christ obtains forgiveness...

As the second part of repentance we add faith in Christ. The Gospel, in which the forgiveness of sins is freely promised concerning Christ, should be presented to consciences in these terrors. They should believe that, for Christ's sake, their sins are freely forgiven. This faith cheers, sustains, and enlivens the contrite, according to Romans 5:1, "Since we have been justified by faith, we have peace with God." This faith obtains the forgiveness of sins. It justifies before God, as the same passages testifies, "since we have been justified by faith." This faith shows the distinction between the contrition of Judas and Peter, of Saul and David. The contrition of Judas or Saul is useless because faith is not added. Faith grasps the forgiveness of sins, given as a gift for Christ's sake. So the contrition of David or Peter helps because faith, which takes hold of the forgiveness of sins granted for Christ' sake is added to it....This faith grows gradually and throughout the entire life, struggles with sin, in order to overcome sin and death. Love follows faith, as we have said above, so childlike fear can be clearly defined as anxiety that has been connected with faith, that is, where faith comforts and sustains the anxious heart. It is slavish fear when faith does not sustain the anxious heart.
~BOC, AP, XII (V), 35-38