2 Corinthians 2:2

καὶ τίς ὁ εὐφραίνων με; Who then is he that maketh me glad? The καί makes the question more emphatic, implying that in that case there would be distressing incongruity: comp. 2 Corinthians 2:16; Mark 10:26; Luke 18:26; John 9:36. Winer, p. 545. This use of καί is classical. Blass § 77. 6.

ὁ λυπούμενος ἐξ ἐμοῦ. He that is made sorry by me. The sorrow is regarded as passing out of (ἐξ) his heart into theirs: he is the source of the pain. The singular (which is necessary as coordinate with ὁ εὐφρ.) sums up the Corinthian Church as one individual. As yet there is no direct reference to the special offender. Had he been meant, the Apostle would have expressed himself very differently.