As regards "every nation of men", God has determined "the boundaries of their dwelling" (Acts 17: 26). This stems from the judgment of the tower of Babel when "Jehovah scattered them thence over the face of the whole earth" (Gen. 11: 9). Previous to this, the whole of mankind was one people (see v6), though presumably there were already many superficial physical differences. What bonded them together and what divided them afterwards, was language. Culture, skin–colour, facial structure and other features may serve to help define a nation, but the pre–eminent distinction is language.
It needs to be understood, however, that God’s arrangement for men as regards the earth has nothing at all to do with his arrangements for the Assembly, the heavenly company. Paul speaks of how Christ has purified to Himself a "peculiar people" (Titus 2: 14)—"people", not 'peoples'. Of course racial distinctions were made in the early years of the history of the assembly (see Acts 6: 1; 15: 23, 29) but this is because the truth of Jew and Gentile united in one body (see Eph. 3: 6) had not been revealed at that time. The mature Christian position is given in Ephesians 2: "For he is our peace, who has made both one, and has broken down the middle wall of enclosure, having annulled the enmity in his flesh, the law of commandments in ordinances, that he might form the two in himself into one new man, making peace; and might reconcile both in one body to God by the cross … So then ye are no longer strangers and foreigners, but ye are fellow–citizens of the saints, and of the household of God … in whom ye also are built together for a habitation of God in [the] Spirit" (vs 14–16, 19, 22).
If the truth of this was fully understood, the 'polite' racism (usually centred on skin–colour) that exists in some Christian circles would rapidly disappear. Our thoughts need to be formed by what God has said, rather than by human prejudices. It is to be feared that the insidious effects of the teachings of Charles Darwin as regards racial superiority have more influence in some minds than the apostle’s doctrine.
In one sense, there are only two kinds of men in the sight of God—the old man (what we are naturally as descended from Adam) and the new man (Christ displayed in the life of the believer). Prejudice is a mark of what we are naturally, but the Word of God as regards the new man is explicit: "wherein there is not Greek and Jew, circumcision and uncircumcision, barbarian, Scythian, bondman, freeman; but Christ [is] everything, and in all" (Col. 3: 11).