These two verses are very closely parallel in structure. As the footnotes on punctuation in the UBS Greek text show, the second part of each verse has sometimes been taken as questions, like verses 17 and 19. However, verses 17-18 and 19-20 form separate units, so most editions and translations take the present verses as statements.

The conditions introduced by If are unreal, as Revised Standard Version‘s should and Good News Bible‘s “were to” indicate. The two occurrences of … should say can be expressed as “suppose”; for example, “Suppose the foot should say.”

The second half of each of these verses contains a double negative, literally “not for this reason is it not of the body.” Most translations turn this into a positive statement that makes this phrase much clearer. Good News Bible‘s “would not keep it from being a part” is easier in English than make it any less a part. Another way of translating this is “that does not mean it is no longer a part.” In some cases it may be better to translate as a rhetorical question: “That would not keep it from being a part of the body, would it?”

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 .