From here to the end of the chapter, as the paragraph division in the UBS Greek text suggests, Paul turns to another aspect of the same question, that of the “weaker brethren.” These are the less mature Christians for whom idols still have some real existence.

This before knowledge is implied. The meaning is “not everyone has this mature kind of knowledge of which we have been speaking.”

Both the text and the meaning of the words translated some … to idols are uncertain. The UBS Greek text is literally “but some in the custom until now of the idol as meat-offered-to idols eat.” Instead of “custom” many manuscripts have “conscience,” which is a similar word in Greek. But this text is almost certainly influenced by the fact that conscience occurs later in the verse. “Custom” is the most likely word here. It is clear that an idol refers to idols in general, not to a particular idol. Some translations spell out in greater detail what is meant by being … accustomed to idols, either “idolatry” (Revised English Bible), or (perhaps too generally) “the old ideas” (Die Bibel im heutigen Deutsch). The danger of the translation “idolatry” is that it might wrongly suggest that these Christians were still taking part in the worship of idols. A possible translation is, then, “Some people have been so used in the past to worshiping idols, that to this day….” “To this day” refers, not directly to eating meat sacrificed to idols, but to being used to a former way of thinking about idols.

The sentence their conscience, being weak, is defiled may be translated “because their conscience is weak, they feel that they are defiled….”

Paul uses the word conscience frequently in this letter; see also 8.10, 12; 10.25, 27; 2 Cor 1.12; 4.2; 5.11. Its earlier meaning was “consciousness.” It is especially used of a bad conscience, that its, the consciousness of having done something wrong. In this verse the meaning conscience and “consciousness” are combined, as Good News Bible‘s addition of the words “they feel” shows. Many languages must express the idea of conscience with a phrase. In such cases one may say, for example, “their ability to discern between right and wrong is weak, and they feel…” or “they have difficulty deciding between what is right and wrong, and they feel….”

Quoted with permission from Ellingworth, Paul and Hatton, Howard A. A Handbook on Paul’s First Letter to the Corinthians, 2nd edition. (UBS Handbook Series). New York: UBS, 1985/1994. For this and other handbooks for translators see here .