Yesterday in the Daily Office the Gospel reading was Luke's version of the confession of St. Peter that Jesus is Lord. Today at Morning Prayer the Gospel reading is from John's Passion Narrative. It's Peter's denial that he knows Jesus.
I hadn't noticed the convergence before. Obviously it's deliberate, and I appreciate it. It's an effective way to remind us, just before Lent begins, that we too can be both saint and sinner, and sometimes in the same day or even the same breath.