Jamieson, Fausset and Brown on Philippians 3:12

12. Translate, "Not that I," &c. (I do not wish to be understood as saying that, &c.).

attained--"obtained," namely, a perfect knowledge of Christ, and of the power of His death, and fellowship of His sufferings, and a conformity to His death.

either were already perfect--"or am already perfected," that is, crowned with the garland of victory, my course completed, and perfection absolutely reached. The image is that of a race course throughout. See 1Co 9:24; He 12:23. See Trench [Greek Synonyms of the New Testament].

I follow after--"I press on."

apprehend ... apprehended--"If so be that I may lay hold on that (namely, the prize, Php 3:14) for which also I was laid hold on by Christ" (namely, at my conversion, So 1:4; 1Co 13:12).

Jesus--omitted in the oldest manuscripts. Paul was close to "apprehending" the prize (2Ti 4:7, 8). Christ the Author, is also the Finisher of His people's "race."