If you are not familiar with the works of St. Peter Chrysologus ("golden words") you are really missing out! He has some really beautiful and deep insights into the faith.
Do not fear, Peter, on account of your denial; John, on account of having fled; all of you, on account of having deserted me, of forming judgments about me with every one of your thoughts devoid of faith, and of still not believing even though you see me. Do not fear, it is I, who have called you by means of grace, have chosen and pardoned you, have sustained you by my steadfast kindness, have supported you with my love, and out of goodness alone I now take you back, because when a father receives his son, and when affections recovers its own, neither one is able to see any faults.
--St. Peter Chrysologus, Sermon 81, par. 3
Special thanks to Pastor William Weedon for making this and other great patristic quotes available through his blog.