4. his own work--not merely his own opinion of himself.
      have rejoicing in himself alone--Translate, "Have his (matter for) glorying in regard to himself alone, and not in regard to another (namely, not in regard to his neighbor, by comparing himself with whom, he has fancied he has matter for boasting as that neighbor's superior)." Not that really a man by looking to "himself alone" is likely to find cause for glorying in himself. Nay, in Ga 6:5, he speaks of a "burden" or load, not of matter for glorying, as what really belongs to each man. But he refers to the idea those whom he censures had of themselves: they thought they had cause for "glorying" in themselves, but it all arose from unjust self-conceited comparison of themselves with others, instead of looking at home. The only true glorying, if glorying it is to be called, is in the testimony of a good conscience, glorying in the cross of Christ.

JFB.