This "turn the other cheek" teaching from Jesus is correctly recognized as calling Christians to non-resistance. Over the years there has been some controversy over whether this passage means that Christians cannot fight in wars or defend their homes and family from threats to life and property. While it is possible that Christians must consider this passage in such situations, it is also important that Jesus does not include those kinds of threats in his illustrations of how to practice the Christian principle of non-resistance.
In this study, we notice that Jesus calls his followers--anyone who wants to practice what is genuine righteousness--to follow his lead in coming alongside others as friends. These others are those who treat one's self wickedly, such as an insulting and belittling slap in the face or a lawsuit to forcibly claim property from you. Jesus earned a reputation as "friend of sinners," and he calls us to do likewise.
Matthew 5: 33-37
"Cross my fingers, hope to die, stick a needle in my eye!" As kids, we might have vowed this silly vow to assure someone else that they could believe what we were telling them. As adults, we have other rituals: "Put it in writing"; "Shake on it"; or, "I promise." In the teaching in this part of his Sermon on the Mount, Jesus calls Christians back to God's righteous way of simply telling the truth. Always. Only the truth.
Since the beginning of marriage, people have debated the legitimate reasons for divorce. These debates have only increased in modern America due to "no-fault" divorce laws. Disciples of Jesus must answer those questions by starting with what the Lord has taught on the matter. In this brief part of the Sermon on the Mount, Jesus instructs disciples in a way that transcends the debates and moves us to live in the light of the Gospel.
It is tempting for disciples of Jesus to let their eyes wander to things they might never let there hands reach for. Jesus teaches his disciples to recognize this as a sign that the heart continues to need his transforming power for righteousness. This is exactly what he came to provide for all who will believe in him.