The words "Barbarian" and "Scythian" occur together in Col. 3:11, in the context of the body of Christ (3:10). I would like to explore the senses and significance of these two words (and their relatives) in this post.
First, Barbarian. This word and its relatives appears in the following passages.
Acts 28:2, "And the barbarous people showed us no little kindness: for they kindled a fire, and received us every one, because of the present rain, and because of the cold."
Rom. 1:14, "I am debtor both to the Greeks, and to the Barbarians; both to the wise, and to the unwise."
1 Cor. 14:11, "Therefore if I know not the meaning of the voice, I shall be unto him that speaketh a barbarian, and he that speaketh shall be a barbarian unto me."
Col 3:11, "Where there is neither Greek nor Jew, circumision nor uncircumcision, Barbarian, Scythian, bond nor free: but Christ is all, and in all.
Looking at all of these verses together, it would appear that the word "barbarian" connotes a "foreigner." In Rom. 1:14, they are non-Greeks (and therefore unwise; 1 Cor. 1:22). In 1 Cor. 14:11, the sense seems to be a foreigner or stranger. Bear in mind that Greek was the universal language of Paul's day, as English is in ours (Acts 21:37, 39; Eccl. 1:9-10!). But note in Acts 28:2 that the barbarous people are within the Roman empire, for Melita is ruled by Publius, obviously a Roman due to his Latin name (28:7). So these "barbarians" are not wild people, since they are subject to Rome; the sense of "barbarous" is the natives of the island, probably non-Greek.
Finally coming to our text in Col. 3:11, Jews are contrasted with Greeks (non-Jews), who are distinguished from Barbarians (non-Greeks), inside or outside the Roman empire. But who are the Scythians...? They are not mentioned anywhere else, except in a passage stressing the comprehensive unity of the body of Christ. Racial, social (bond nor free), even gender (Gal. 3:28a) barriers in the physical realm do not affect our unity in the Spirit (Gal. 3:28b). So being a Scythian does not exclude you from the unity in Christ. A brief look at Wikipedia or an encyclopedia sheds light on the non-Roman character of the Scythian. They were peoples on the outskirts of the empire, in places like southern Russia. I think that Paul may have included them in this passage on the scope of those in Christ to show that just because someone is outside the Roman empire, i.e. the civilized world, does not mean they can't be in Christ, any more than being a non-Greek barbarian does. Praise God, he will take the "savage" Scythians into his Son, if they will only believe!