Connect with the matter of the two preceding verses. Grace was given me to preach Christ and to enlighten men as to the long-hidden mystery of the admission of the Gentiles, in order that now, etc.
Now
In contrast with all ages.
Principalities and powers
Good angels. See on Eph 1:21.
By the Church (διά)
Better, through, as Rev. By means of the Church. This agrees with what was said of the Church as the fullness of God, Eph 1:23.
Manifold wisdom (πολυποίκιλος σοφία)
A very striking phrase. The adjective occurs only here, and means variegated. It is applied to pictures, flowers, garments. Ποίκιλον is used in the Septuagint of Joseph's coat, Gen 37:3. Through the Church God's wisdom in its infinite variety is to be displayed - the many-tinted wisdom of God - in different modes of power, different characters, methods of training, providences, forms of organization, etc.