In British civil law, there is a concept known as the Neighbour Principle designed to establish what is called "duty of care". Effectively, the neighbour principle helps determine at exactly what point someone else becomes your problem.
The neighbour principle determines that another person is your neighbour if they are so closely and directly affected by your actions that you ought to have them in reasonable contemplation. In simpler terms, that means if your actions can affect a person, you have to consider that person.
For example, in the UK, the postman comes right to our door and posts letters through a slot. It is, therefore, reasonably foreseeable that if you leave a hose pipe lying in the driveway, an unobservant postman, or even an observant postman if there is something obstructing his view, may fall over the hosepipe and receive injuries. You would therefore be liable for those injuries.
But let's say you come across that same postman having fallen over in the streets. You didn't leave anything for him to trip, you didn't push him, you didn't even see him fall, you just found him. Legally, you can leave him there with no repercussions. Morally? According to Jesus, this man is still your problem.
This is one of many examples of where God's laws are superior to man's laws. Whereas man's laws allow you to be pretty much aloof as long as you do not cause harm (and often, even if you do cause harm), God expects us to care for everyone regardless of our direct relationship with them.
In fact, in the parable of the Good Samaritan, Jesus adds an extra layer: Racial tensions, and religious differences. To His Jewish audience, the Samaritans were rather undesirable. Jews just didn't associate with Samaritans. So, for a Samaritan to be used as the hero of the story is rather significant. We're not just talking strangers, we're talking enemies.
Now pay attention to this: The whole parable resulted from an inquiry about eternal life. "What must I do to inherit eternal life?" a Jewish man asked. So Jesus asked him what he thinks the answer is based on the law. The Jew responded "Love God with all your heart, soul, strength and mind, and love your neighbour as yourself". And Jesus said this is correct! This is how to obtain eternal life. But then He told this parable to establish who is your neighbour? It is not just anyone so closely and directly affected by your actions that you ought to have them in reasonable contemplation. It's literally anyone you encounter. Friends, strangers, enemies. If you find someone struggling, and it is within your ability to help them, even if it's a simple phone call to pass them off to someone more capable than you are, it is your duty to do it.