Let every man prove his own work: the apostle, by a man’s
own work here, understands his own actions and manners, which he would have every man to busy himself to search, try, and examine by the Divine rule, whether they be conformable to the will of God, yea or no;
and then, he saith,
shall he have rejoicing in himself alone, and not in another; a man shall (if he findeth his work such as is agreeable to the will of God) have a cause to rejoice in himself; not in the merit or perfection of his works, but in his own works; not in others; that is, he shall rejoice in something which God hath wrought in and by him, and not in others. This the apostle wisely propounds, as a means to bring a man to know his own measures; it being a great error for men to measure themselves by the measures of other men, their perfections by others’ imperfections.