I think it should be * ff * and means* following *, that is, continue to read the verses that follow. [Hope that makes sense. I fear my wording is clumsy.]
I am reasonably certain of that, the *f *means “and the following verse.” So, 1 Cor 1:27f means 1 Corinthians, chapter 1, verse 27 and the following verse, i.e., and verse 28.
I am also reasonably certain that, the ff is the plural of f and means “and the following verses,” and the two or more following verses.
DISCLAIMER: Catholic Answers has turned over the archive to Catholic-Questions.org and no longer owns, manages, or moderates the forums. For additional apologetics resources please visit www.catholic.com.