5. Doesn't Romans 14:5 say each man is free to keep whatever day he wants, whether Sabbath or Sunday or another day?
Neither Sabbath nor the first day of the week is mentioned in this passage. Since the verse is sandwiched between verses dealing with the issue of vegetarianism (v.1-3 and v. 6), perhaps some believers were regarding certain days as "special" (v. 6) in the sense of being dedicated to the eating of vegetables only (meat being considered by them, "unclean," v. 14). Or this could be another reference to the Judaizing tendency to insist on the observance of Old Covenant feast days, with vegetarianism being combined with this practice (in the kind of syncretism that existed at Colosse). The overall principle is stated in Rom. 14:17, "For the kingdom of God is not a matter of eating and drinking." The 4th Commandment was never a matter of eating and drinking, but ceremonial practices of the Old Covenant were. It is they which are, again, being addressed.
Neither Sabbath nor the first day of the week is mentioned in this passage. Since the verse is sandwiched between verses dealing with the issue of vegetarianism (v.1-3 and v. 6), perhaps some believers were regarding certain days as "special" (v. 6) in the sense of being dedicated to the eating of vegetables only (meat being considered by them, "unclean," v. 14). Or this could be another reference to the Judaizing tendency to insist on the observance of Old Covenant feast days, with vegetarianism being combined with this practice (in the kind of syncretism that existed at Colosse). The overall principle is stated in Rom. 14:17, "For the kingdom of God is not a matter of eating and drinking." The 4th Commandment was never a matter of eating and drinking, but ceremonial practices of the Old Covenant were. It is they which are, again, being addressed.