It’s vital to remember that upstanding behavior can come from both Christian and non-Christian sources. My neighbor of a different faith or philosophy can show me where I’m failing to live out my life in Christ.
It’s also important to remember that decidedly “un-Christian” behavior can come from non-Chrisitans and Christians alike. Every single one of us has a darkened nous that suffers temptation, anguish, addiction, and struggle. “For all have sinned and fall short of the glory of God” (Romans 3:23).