"What does it mean to love one another?"

Jesus knew that relationships are the most valuable asset that we have, but at times the most difficult to maintain. That’s why in John 13:34 Jesus taught, “A new command I give you: Love one another. As I have loved you, so you must love one another.” Then He added, “By this everyone will know that you are my disciples, if you love one another” (verse 35).
The “one another” in these verses is a reference to fellow believers. A distinguishing mark of being a follower of Christ is a deep, sincere love for brothers and sisters in Christ. The apostle John reminds us of this fact elsewhere: “He has given us this command: Anyone who loves God must also love their brother and sister” (1 John 4:21).
In giving this command, Jesus did something the world had never seen before—He created a group identified by one thing: love. There are many groups in the world, and they identify themselves in any number of ways: by skin color, by uniform, by shared interest, by alma mater, etc. One group has tattoos and piercings; another group abstains from meat; yet another group wears fezzes—the ways people categorize themselves are endless. But the church is unique. For the first and only time in history, Jesus created a group whose identifying factor is love. Skin color doesn’t matter. Native language doesn’t matter. There are no rules about diet or uniforms or wearing funny hats. Followers of Christ are identified by their love for each other.
The early church demonstrated the type of love Jesus was talking about. There were people in Jerusalem from all over the known world (Acts 2:9–11). Those who were saved got together and immediately began meeting each other’s needs: “All the believers were together and had everything in common. They sold property and possessions to give to anyone who had need” (Acts 2:44–45). This was love in action, and you can be sure it made an impression on the people of that city.
Jesus’ statements in John 13:34–35 raise a couple of other questions that may be good to answer. First, how does Jesus love? He loves unconditionally (Romans 5:8), sacrificially (2 Corinthians 5:21), with forgiveness (Ephesians 4:32), and eternally (Romans 8:38–39). At the same time, Jesus’ love is holy—characterized by transcendent moral purity—because He is holy (Hebrews 7:26). The culmination of Christ’s amazing love for us is His death on the cross, burial, and bodily resurrection (1 John 4:9–10). Believers are to love each other like that.
Second, “How then can the believer in Christ love as Christ loved?” The believer in Christ has the Holy Spirit living within him (1 Corinthians 6:19–20). By obeying the Spirit, through the Word of God, the believer can love like Christ does. He shows that unconditional, sacrificial, forgiving love to fellow believers, but it doesn’t stop there. He also shows the love of Christ to friends, to family members, to coworkers, etc. (Ephesians 5:18–6:4; Galatians 5:16, 22–23). Even enemies are the recipients of Christ’s love (see Matthew 5:43–48).
Christ’s love displayed through the believer is unlike the “love” generated by the flesh, which can be selfish, egotistical, unforgiving, and insincere. First Corinthians 13:4–8 gives a wonderful description of what Christ’s love will be like in and through the believer who walks in the Spirit.
People don’t naturally love with a 1 Corinthians 13-type love. To love like that, there must be a change of heart. A person must realize that he is a sinner before God and understand that Christ died on the cross and rose again to provide him forgiveness; then he must make the decision to accept Christ as his personal Savior. At that point he is forgiven by Christ and receives God’s gift of eternal life—in fact, he becomes a participant in the divine nature (2 Peter 1:4). In Christ he knows that he is genuinely loved by God. The new life the believer receives includes a new capacity to love like Christ loves, for the believer now has living within him the unconditional, sacrificial, forgiving, eternal, and holy love of God (Romans 5:5).
To love one another is to love fellow believers as Christ loves us. Those who love like Christ in the Holy Spirit’s power will give evidence that they are disciples, or learners, of Jesus Christ.
Read more: http://www.gotquestions.org/love-one-another.html#ixzz3EkoGuvPp

"Is it right for a Christian to date or marry a non-Christian?"

For a Christian, dating a non-Christian is unwise, and marrying one is not an option. Second Corinthians 6:14 (KJV) tells us not to be “unequally yoked” with an unbeliever. The imagery is of two incompatible oxen sharing the same yoke. Instead of working together to pull the load, they would be working against each other. While this passage does not specifically mention marriage, it definitely has implications for marriage. The passage goes on to say that there is no harmony between Christ and Belial (Satan). There can be no spiritual harmony in a marriage between a Christian and a non-Christian. Paul goes on to remind believers that they are the dwelling place of the Holy Spirit, who inhabits their hearts at salvation (2 Corinthians 6:15-17). Because of that, they are to be separate from the world—in the world, but not of the world—and nowhere is that more important than in life’s most intimate relationship—marriage.

The Bible also says, “Do not be misled: ‘Bad company corrupts good character’ (1 Corinthians 15:33). Having any kind of intimate relationship with an unbeliever can quickly turn into something that is a hindrance to your walk with Christ. We are called to evangelize the lost, not be intimate with them. There is nothing wrong with building quality friendships with unbelievers, but that is as far as it should go. If you were dating an unbeliever, what would honestly be your priority, romance or winning a soul for Christ? If you were married to an unbeliever, how would the two of you cultivate a spiritual intimacy in your marriage? How could a quality marriage be built and maintained if you disagree on the most crucial issue in the universe—the Lord Jesus Christ?