Unauthorized Immigration versus Authorized Immigration

Imagine you own a couple acres of land, enough to have decent breathing room. Now imagine that you let people whom you have never known before onto your land, to live on it and work on it if they met a certain criteria you have set for such a situation. Now imagine that some other people start showing up on your land that you did not approve to be there. In each case the people being approved or the people avoiding your approval process could be good or evil, just or injust, clean or dirty, etc. They are people and they come in all different kinds of ways. Now ask yourself, even knowing that some could be good and some could be not so good, who poses the greater risk to your family and the people you have already approved to be on your land?

Yes, my qustion is geared to be a moral one and that is where I set my priority in such a debate.

Addendum From a Later Time...
I wish to add to the above post without modifying the original content. I geared the above situation to lead to one answer, in short I wasn't making an honest effort to understand anything. I still believe we need to protect ourselves, our nation and the ideals it is founded on. But, we have to be careful of using that as an excuse to treat others as objects and not as people. It is self-evident that all people are created equal under God. And we all have a right to life, liberty and the pursuit of all things good and true. It is our responsibility to our fellow man to make sure that we do as much in our power as we are healthily capable of doing to see that all of humankind keep these rights.