Friendship is an important part of a healthy life; both being a friend and having friends. We are not meant to live our lives in isolation from one another and friends keep a great diversity in our lives. Some people play it safe and surround themselves with people who think like they do, act like they do, talk like they do, walk like they do, and sometimes even eat like they do. Others take greater risk in their relationships and look for a good diversity of people to call friends; people from different backgrounds, from different economic statuses, even different beliefs. It is not that they have a check list and go around tagging people as a friend; they just tend to be more open and generous in their giving to people and attract friends. This adds a great richness to their lives.
Now let's add to this context Jesus' teaching about not judging. If we want to be the person who attracts diverse friendships, as God wants us to be, then we must first learn to accept them as they are, as our Father does. His love does not start after we accept Jesus. He loved us from the moment he started forming us in our mother's womb, as he loves everyone because he has formed everyone. Unfortunately this love will not save us because we have to go through a reconciliation with God due to our sin, and that does not happen until we realize the state we are in and accept the gift of Jesus to change that state. Then we are able to enjoy a rich fellowship with our Father.
However, we cannot start a relationship with someone with the idea of changing them. We cannot change anyone because the change takes place with the heart and only our Creator can effect change there. However, he does use us to show love to the people we come to call friend. He uses us to influence people so that they can ask questions or even appreciate the unconditional love we show them. It is through love that the Spirit is able to change hearts. We would like to think that the great multitude of ordinary people who surrounded Jesus came for the teaching but they didn't. They came because of Jesus' compassion, his gentle, healing touch. To the teaching on not judging Jesus adds this interesting instruction:
Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and then turn and tear you to pieces. (Matthew 7:6)
It sounds a bit harsh but do not be thrown off by the imagery of dogs and pigs. We give these animals what is appropriate for them to consume. What is a dog going to do with sacred objects? What is a pig going to do with pearls? They will chew on them and walk over them because they do not understand their worth. This is like us trying to share the deeper things of God with those who have no relationship with Jesus. It is like us arguing the point of salvation with someone who has not yet been prepared by the Spirit. Our friends do not know what to do with these precious things because they do not understand their value. Jesus is not calling the unsaved of this world dogs and pigs but is simply giving us an allegory for better understanding.
The bottom line is - keep it simple. Be the best friend you can be to people. Show love through your kindness, attention, good deeds, sacrifice. Friendship requires sacrifice. Never enter into the sins of your friendships but neither walk away just because they sin. At this point they are doing what comes natural. Look at who Jesus spent all his time with, and he enjoyed them, but he did not enter into their sin with them. When you consider what he taught to the crowds it was simple stuff and he left the deeper things for his disciples, yet the crowds were amazed at how simple Jesus made it for understanding. The deeper things he told in parables so that those who were ready to understand could understand without confusing those who were not there yet.
Understand this though: to not be a friend to sinners is flying in the face of the command we were given, to "go". If all we have in our lives is fellow believers then I believe we are doing wrong and we are failing the mission. We have to allow people to enter into our lives and we must enter into theirs to love them and through our actions reveal the heart of the Father. Do this and see the change the Spirit brings to their hearts using the influence of the love and acceptance you show them. It really is simple; love God and love people.