Brethren, I count not myself to have apprehended,.... That for which he was apprehended of Christ: he had not attained to perfect knowledge, was not come to the mark, had not received the prize, or laid hold on eternal life; though he had received so much grace, and such gifts, as had qualified him for an apostle; and he had been so many years in that office, and had so great a knowledge in the mystery of the Gospel, and had laboured in it more abundantly than others, and with great success; and even though he had been caught up into the third heaven, and had heard unspeakable words, not lawful to be uttered, 2Co 12:2, yet he had no such opinion of himself, as if he was perfect: by which way of speaking, he tacitly strikes at the arrogance and vain confidence of false teachers, that pretended to perfection; and in this way led the brethren to conclude, that they could never have arrived to it, since so great an apostle had not; some copies read not "yet", and so the Ethiopic version:but this one thing [I do]; which he was intent upon, constantly attended to, and earnestly pursued; it was the main and principal thing he was set upon, and which he employed himself in; and which engrossed all his thoughts, desires, affections, time, and labour; see Ps 27:4.
The Syriac version reads, "this one thing I know"; signifying that whatever he was ignorant of, and however imperfect his knowledge was in other things, this he was full well apprized of, and acquainted with.