In Scripture the nations do not seem so much to have an open border law as to not have a law preventing sojourners to come in. An open border law would imply that there would be a positive law either allowing or disallowing people to come in.
But more than the open border issue vs. no open border I am against what has been done with reference to those already inside. I am against the idea that foreigners whether illegal aliens or legal should not be entitled to an equal right to a fair and equal trial by law just as much as we citizens are.
16 And I charged your judges at that time, saying, Hear the causes between your brethren, and judge righteously between a man and his brother, and the sojourner that is with him.
17 Ye shall not respect persons in judgment; ye shall hear the small and the great alike; ye shall not be afraid of the face of man; for the judgment is God’s: and the cause that is too hard for you ye shall bring unto me, and I will hear it. (Deuteronomy 1:16-17 ASV)
That which cannot be done without a violation of the law of nature also called the moral law must needs be a violation of the moral law of God. There are certain practices or laws which if used or practiced in civil government in their own nature would be sin or violations of the moral law of God. Although not every sin or transgression of the moral law is to be punished by the civil powers or outlawed by the civil law of any commonwealth or nation, yet there are some civil policies and civil laws which in their own nature are transgressions of the moral law. Forbearance to punish or make a civil law against some open sins is not necessarily a violation of the moral law. But to do that which is in its own nature a transgression of the moral law as a matter of civil policy is to violate the moral law in matter of civil government, civil law, or policy. In this way the moral law of God may be truly said to not merely give principles or values that one can choose to use or not, but it is a binding rule for civil government and policy.