Thought I would share this very useful resource. You can easily find every place a patristic writer (at least the ones in Schaff's ANF, NPNF1 and NPNF2 series) quotes or apparently alludes to a passage of scripture. You can also click on a heading and it will take you to the resource at CCEL to get the full context.
Church Fathers Scripture Search Engine
Church Fathers Scripture Search Engine
