The Greek conjunction ei kai is a concessive conditional — meaning 'even if' or 'although.' It introduces a condition that does not necessarily negate the main point but acknowledges a challenging circumstance while asserting that the conclusion holds regardless. It appears frequently in Paul's letters in contexts of hardship and perseverance.
Ei kai is the grammar of gospel perseverance — 'even if' I suffer, even if outwardly I am wasting away, the inner reality and final hope remain sure. Paul uses it in 2 Corinthians 4:16 ('even though our outer self is wasting away') and Philippians 2:17 ('even if I am to be poured out') to express costly faithfulness. The concessive form acknowledges real difficulty while refusing to let it be the final word.