But let every man prove his own work, and then shall he have rejoicing in himself alone, and not in another.

People's New Testament

6:4 But let every man prove his own work. Instead of commenting upon the weaknesses of others, let him test his own work.

Then shall he have rejoicing in himself alone, and not in another. If his work stands the test, there he can rejoice in it alone, not because he is superior to another.

Wesley's Notes

6:4 But let every man try his own work - Narrowly examine all he is, and all he doeth. And then he shall have rejoicing in himself - He will find in himself matter of rejoicing, if his works are right before God. And not in another - Not in glorying over others.

Jamieson-Fausset-Brown Bible Commentary

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.

Matthew Henry's Concise Commentary

6:1-5 We are to bear one another's burdens. So we shall fulfil the law of Christ. This obliges to mutual forbearance and compassion towards each other, agreeably to his example. It becomes us to bear one another's burdens, as fellow-travellers. It is very common for a man to look upon himself as wiser and better than other men, and as fit to dictate to them. Such a one deceives himself; by pretending to what he has not, he puts a cheat upon himself, and sooner or later will find the sad effects. This will never gain esteem, either with God or men. Every one is advised to prove his own work. The better we know our own hearts and ways, the less shall we despise others, and the more be disposed to help them under infirmities and afflictions. How light soever men's sins seem to them when committed, yet they will be found a heavy burden, when they come to reckon with God about them. No man can pay a ransom for his brother; and sin is a burden to the soul. It is a spiritual burden; and the less a man feels it to be such, the more cause has he to suspect himself. Most men are dead in their sins, and therefore have no sight or sense of the spiritual burden of sin. Feeling the weight and burden of our sins, we must seek to be eased thereof by the Saviour, and be warned against every sin.