Jamieson, Fausset and Brown on 1 Corinthians 10:28

28. if any man--a weak Christian at table, wishing to warn his brother.

offered in sacrifice unto idols--The oldest manuscripts omit "unto idols." At a heathen's table the expression, offensive to him, would naturally be avoided.

for conscience' sake--not to cause a stumbling-block to the conscience of thy weak brother (1Co 8:10-12).

for the earth is the Lord's, &c.--not in the oldest manuscripts.