As unknown, and yet well known; as dying, and, behold, we live; as chastened, and not killed;
Unknown, and yet well known - "unknown" in our true character to, and held 'ignoble' by, those who "evil report" of us; "well known" to those who holds us in "good report" (2 Corinthians 6:8): above all, "well known" to God (1 Corinthians 13:12; 2 Corinthians 5:11; 2 Corinthians 11:6).
Dying ... live (1 Corinthians 1:25; 2 Corinthians 1:9; 2 Corinthians 4:10-11; 2 Corinthians 10:1; 2 Corinthians 11:23: cf. note, 5:5).
Behold breaks through the even tenor of the sentence, and calls attention to something beyond all expectation.
Chastened, and not killed (Psalms 118:18).