I sent him therefore the more carefully, that, when ye see him again, ye may rejoice, and that I may be the less sorrowful; rather, I send him (epistolary aorist, as Philippians 2:25), I send him with the letter.
Perhaps "again" is better taken with the following clause; "that when ye see him, ye may again rejoice." Note St. Paul's ready sympathy with the Philippians: their restored joy will involve a diminution of his sorrow.
Mark also the implied admission that sorrows must still remain, though spiritual joy brightens and relieves them. "Sorrowful, yet always rejoicing" (2 Corinthians 6:10).