Adam Clarke on Galatians 6:4

Prove his own work - Let him examine himself and his conduct by the words and example of Christ; and if he find that they bear this touchstone, then he shall have rejoicing in himself alone, feeling that he resembles his Lord and Master, and not in another - not derive his consolation from comparing himself with another who may be weaker, or less instructed than himself. The only rule for a Christian is the word of Christ; the only pattern for his imitation is the example of Christ. He should not compare himself with others; they are not his standard. Christ hath left us an example that we should follow his steps.