Today's verses lined up pretty well again. In the New Testament reading, we see Peter showing belief in Jesus, confessing him as the Son of God. In Genesis, we have Sarah laughing at the thought of God's absurd promise. While neither was a perfect person and both certainly had their failures, this moment for each of them is very different, and that difference is our coming to terms with God keeping his promises. Of course, God was faithful to both people, so it's not all about us!