I have rather frequently encountered Christian apologists making the claim that evolution and atheism are the foundations of the institution of slavery in America. Though this claim more often relates to eugenics and social Darwinism, the backbone running through this claim relates to institutional racism specifically in the form of slavery. I disavow social Darwinism as a dogmatic belief system. It is not and never was based on empirical science nor the theory of evolution. It is most unfortunate that Christians are often the party to attempt to make the connection between social Darwinism and evolution because it is Christianity that has a clear historical connection with slavery and later ethnic injustices in America. Before Christians criticize social Darwinism, I think it meet that the Christian consider Paul's advice regarding slaves.
Paul states in I Corinthians 7:17-24 reads:
But as God hath distributed to every man, as the Lord hath called every one, so let him walk. And so ordain I in all churches. Is any man called being circumcised? let him not become uncircumcised. Is any called in uncircumcision? let him not be circumcised. Circumcision is nothing, and uncircumcision is nothing, but the keeping of the commandments of God. Let every man abide in the same calling wherein he was called. Art thou called [being] a servant? care not for it: but if thou mayest be made free, use [it] rather. For he that is called in the Lord, [being] a servant, is the Lord's freeman: likewise also he that is called, [being] free, is Christ's servant. Ye are bought with a price; be not ye the servants of men. Brethren, let every man, wherein he is called, therein abide with God.
In I Corinthians 7, Paul attempts to dissuade the Corinthians from changing their social status regard to marriage, conversion (Gentiles becoming Jews), and slavery. Paul clarifies that his instructions regarding marriage relate to, "the present distress" (7:26) and so it can be implied that Paul's instructions are limited to the "distress" of his generation. Don't forget that Paul is the earliest writer of the New Testament corpus, and he expected Jesus to return in his lifetime. In the above pericope, Paul instructs his readers to "abide in his [social] calling." Though this passage does not entirely imply that it is wrong to consider buying or obtaining freedom, it does nothing to ameliorate the practice or station of slaves in his readers.
In Colossians 3:22, it is stated:
Servants, obey in all things [your] masters according to the flesh; not with eyeservice, as menpleasers; but in singleness of heart, fearing God.
Here the author of Colossians (a pseudo-Pauline reworking of Ephesians), maintains that the servant-slave must work for his master as though working for God. This instruction does nothing to address the status of slaves, and it became, in the Christian South, a basis of a code of slave ethics taught by the slave holder to the slave. A similar verse in the more-likely Pauline work of Ephesians 6:5 reiterates this theme.
Deuteronomy 23:15-16 offers the following imperative regarding a slave that escapes from a master:
Thou shalt not deliver unto his master the servant which is escaped from his master unto thee: He shall dwell with thee, [even] among you, in that place which he shall choose in one of thy gates, where it liketh him best: thou shalt not oppress him.
It is interesting that despite the humanness of this passage that Paul in book of Philemon, returns the escaped slave Onesimus to his master. Paul here has an opportune moment to apply a biblical precept and demonstrate a biblical aversion to slavery. However, there is no such biblical aversion to slavery. Abolish was not served by Paul and his soft approach to slavery. His social ethics discourage social mobility and directly encourage the slave to stay where she is—serving the master as though serving God.