It is surprisingly easy to wear the label "Christian" without actually doing what Jesus tells us to do. The Sermon on the Mount is replete with hard commands and difficult teachings, and when, after his resurrection, Jesus commissions his first followers to go out and make disciples by "teaching the obey everything I have commanded you."
In today's verses, Jesus calls us to be "perfect" as God is perfect. That is not unlike God's command at Mt. Sinai "to be holy for the Lord your God is holy." But neither "perfect" nor "holy" may mean quite what we assume they do.