SORROW (עֶ֫צֶב, H6776; λυπέω, πενθέω; grieve, mourn, be sad).
Christ’s suffering and departure brings sorrow to His disciples’ hearts (John 16:6; cf. Matt 9:15—it is appropriate to mourn when the bridegroom leaves), but it was good that He go away, for then the Comforter would come (the Comforter of the sorrowful). As the woman in childbirth has sorrow but joy at birth, so the disciples’ sorrow will be turned into joy at His return (John 16:21, 22); when they ask and receive, their joy will then be made full.
Second Corinthians is practically a treatise on the necessary sorrow that Christians must inflict on each other as they admonish and correct sin. Paul does not desire to make another painful visit (2:1), nor was his purpose ever just to bring sorrow (2:4). Instead his goal was godly grief, the sort that produces repentance, salvation, zeal, and finally Paul’s own comfort and joy (7:8-13). Hebrews teaches that the Father’s disciplining of His own sons indeed yields the fruit of repentance even though painful at the time (12:11). Peter makes a similar statement (1 Pet 1:6), that our rejoicing is in our imperishable inheritance, even though its genuineness is tested by various trials for a short time. We shall be approved if we suffer unjustly (2:19, 20). So the inheritance of comfort enables us to sorrow with hope.
H. Ridderbos, The Coming of the Kingdom (1950), 185-192.
International Standard Bible Encyclopedia (1915)