Peter's "moment of discovery" occurred when he realized that God’s love and salvation were meant not only for Jews but for Gentiles as well. This revelation came through a vision from God, challenging Peter’s preconceived beliefs about what is "clean" and "unclean." Peter had been resistant to interacting with Gentiles, but through divine intervention — both his vision and Cornelius' visitation by an angel — he understood that God shows no favoritism and accepts all who seek Him, regardless of their background.