“But let each one examine his own work, and then he will have rejoicing in himself alone, and not in another.”
The answer to the self-sufficient person in verse three is self-examination.
But let each one examine his own work,
Arrogant people need to “examine” themselves. The word “examine” means to test something for the purpose of approval, to determine whether it is genuine or not. When we expose ourselves to the objective Word of God, we can truly see ourselves for what we are. The Word is impartial and will not allow us to deceive ourselves. Rigorous self-judgment lets us see ourselves for what we indeed are.
The present tense in “examine” means we must constantly test our spiritual lives. “Be diligent in persisting to test yourself. Make an accurate examination of yourself using the Word of God.”
The word “work” can refer to our behavior or actions. The best way to be objective about ourselves is to examine our lives in light of the Bible. It is very easy to delude ourselves into thinking that we are spiritually greater than others.
and then he will have rejoicing in himself alone,
The failure of others should give us no ground for glory. Criticizing others is no basis for building an honest life before God. However, rejoicing in what God does through us is valid. The proper ground of our glory is strictly what God does through us.
and not in another
Viewing others as less than ourselves spiritually does not, of necessity, make us superior. It does us no good to lift ourselves by disparaging others. Comparing ourselves with others is not the issue; the issue is what we are genuinely in ourselves.
“For we dare not class ourselves or compare ourselves with those who commend themselves. But they, measuring themselves by themselves and comparing themselves among themselves, are not wise. However, we will not boast beyond measure, but within the limits of the sphere which God appointed us—a sphere that especially includes you. For we are not overextending ourselves (as though our authority did not extend to you), for it was to you that we came with the gospel of Christ; not boasting of things beyond measure, that is, in other men’s labors, but having hope, that as your faith is increased, we shall be greatly enlarged by you in our sphere, to preach the gospel in the regions beyond you, and not to boast in another man’s sphere of accomplishment. But “he who glories, let him glory in the LORD.” For not he who commends himself is approved, but whom the Lord commends” (2 Corinthians 10:12-18).
Christians should never compare themselves with others. Legalists always seek to compare their output with that of others. Legalists love to put others down to lift themselves above others. Looking for a spiritual pygmy to measure yourself up against is not a noble goal! By this method, you cannot conclude that you are head and shoulders above other believers. If we want to take a good measurement of where we stand, stand back-to-back with the Lord Jesus.
Principle:
God requires that each of us examine ourselves to be objective with ourselves and the Lord.
Application:
Using the Word of God to examine our souls is the acid test for determining whether we are genuinely spiritual. That is why we must candidly allow the Word to serve as a standard to examine ourselves. None of us like the idea of God’s mark of red ink over much of what we are and do. We want to fancy ourselves without fault or flaw.
“But let a man examine himself, and so let him eat of the bread and drink of the cup” (1 Corinthians 11:28).
Many Christians play the one-upmanship game: “My production is better than your production.” This comparison always hurts our Christian life and fellowship with others because everything we do is by God’s grace. Much of what we do is based on our gifts (special supernatural endowments of grace), of which we cannot claim the credit. Moreover, it is God who determines how much He uses each of us.
“So then each of us shall give account of himself to God” (Romans 14:12).
Much of our service for the Lord is religious shadowboxing. We think we are doing God’s will, but we delude ourselves. What others say about us is irrelevant to God’s plan. The devil will use other believers to get us off track. We think they have no right to treat us that way. We become bitter, sour, and cynical. Everything with us is sour grapes. Our soul has curdled.
This negative attitude will take you out of spiritual circulation. Some of you have not done anything for God in 20 years because the church did not applaud you appropriately for your service. You were not appreciated but criticized. The problem is that you serve people, not God. You are after applause, not service. That is why you left and gave up. In your spiritual retirement, the blessing of God passed you by. You can trace it all back to something someone said about you.

Very good work. God bless you.
Thank you Selorm.
Wonderfully said. His spirit will not leave you